The following quote is from a post by CrossVR but as my reply is both long and in parts deviates into a more general discussion I've avoided cluttering up that thread by posting it as a new comment.

"An SSD that fails is likely to go into a read-only mode that still allows you to recover your data."

Perhaps so, but from my experience that's often not what happens, most of my SSD failures have resulted in the drives being stone-dead, that is completely unresponsive and their data irrecoverable. I'd like to see some comprehensive statistics on this.

There's much that can be said about the reliability of hard drives and SSDs (and other electronic storage media) as well as the role manufacturers have in making reliable storage. I'd argue that their collective actions aren't helpful and overall they have made present-day storage less reliable than it ought to be by virtue of the secretive and proprietary processes they've employed to manufacture their products.

First, it seems to me that all too often we do not bother to consider storage technologies in an holistic way; after all, the management, control and long-term integrity of our data ought to be our first and principal focus, so from the outset we ought analyse how effective current storage technologies are at achieving these goals. My contention is that when we appraise modern electronic storage with that objective in mind then we find that it falls very short of the ideal. If it were not for the fact that at present there is no existing technology that is more reliable and more suited for purpose then I'd suggest that all currently-used technologies are not fit for purpose.

Of course, one cannot justifiably make such a claim if better solutions do not exist, so let me explain why I've ventured forth with such a provocative comment. Before I do I'd add that any detailed analysis of the subject is worthy of a lengthy book, thus—with limited exceptions—involved technical discussion is essentially outside the scope of this post. Therefore, rather than spend time on the minutae of drive failures I'll instead focus on users' data and the essential requirement to protect its integrity for as long as is necessary. Specifically, that must be for as long as users deem said data useful and or relevant. In practice, that could be upwards of many decades, and in some instances data may have to be kept in perpetuity.

That brings me to major concerns I have with existing data storage systems, first is the technologies that both hard disks and SSDs employ are essentially ephemeral in that they are intrinsically fragile. The consequences are that the level of overhead necessary to protect and maintain data integrity over its required lifetime is high; second, in the neverending quest to increase data densities, the developedment of both hard drives and SSDs is continuously being pushed to the limit. Combined, they not only contribute to overall system fragility but also to reduced lifecycles, they increase turnover of hardware and increase maintenance costs.

Moreover, even if hardware does not fail within its nominal replacement schedule, its lifecycle is still of extremely short duration when compared with traditional storage. Again, ongoing upgrades and hardware replacements put a considerable burden on both professional and individual users. Moreover, maintenance and its concomitant costs must be continued throughout the expected lifetime of the stored data, otherwise data integrity would suffer.

Nevertheless, for the most part, professional users—data centers, well-managed server sites, etc.—end up better off than individual users in that (a) they have strict and well-structured backup procedures that ensure the integrity and longevity of users' data, and (b) their infrastructure is such that it's easier for them to follow best practice

On the other hand, users who manage their own data have to take full responsibility for both its integrity and longevity which is a considerable challenge given that many are unaware of the limitations of the technologies they are forced to use. Thus, it's not surprising this group often experiences difficulties in maintaining the integrity of their data across its deemed lifetime.

Such are the limitations of modern electronic storage systems. In the grand scheme of things, whilst present-day technologies offer many advantages over older more traditional storage systems like print and paper documents they nevertheless exhibit some serious drawbacks and disadvantages. Irrespective or whether they're used to store analog or digital data, and unlike their older counterparts, modern storage and retrieval systems cannot offer users set-and-forget long-term data storage that will remain reliable and viable over many decades or even centuries because (as already stated) the technologies necessary to support this level of reliability simply do not yet exist in any practical form. (Yes, I accept some low-density long-term storage systems do exist but for almost all modern applications they're impractical to use.)

As mentioned, all common 'electronic' storage technologies in current use are, by nature, essentially ephemeral. Restated, the information stored in modern data storage and retrieval systems has to be refreshed and regenerated at regular intervals to remain viable. Moreover, in comparison with traditional information storage, modern electronic systems require the interval between data refresh cycles to be very short indeed. For instance, there are many paper-based documents that are many centuries old and the information they contain is still fully viable whereas with digital systems refresh intervals can be as short as the life of a hard disk or SSD or even less—that is as short as several years, five or so at most.

Holistic considerations require one to again draw a comparison between the longevity of traditional information and the ephemeral nature modern storage technologies, so despite my above point about keeping technical details out of the discussion, I have to make brief mention of the limitations of these technologies to justify my assertions.

Going on evidence it's safe to say there's no 100% guarantee (in fact it's unlikely) that data stored in any electronic storage media that's in common usage nowadays will be able to be read in say 20—30 years from now let alone in 50 or 100 years. Simply, we have no electronic technology nor any foolproof system that can guarantee that data can be stored for many decades and still be read faithfully. That this story and these posts are concerned with the short and inadequate service life of hard disks and SSDs only highlights the point.

Why is this so? Well, let's briefly look at various storage technologies currently in use and consider why none is even satisfactory let alone ideal. First, consider cloud storage. To commit one's data to the Cloud means that one must have complete faith in the vendors that offer such services. A quick examination shows that none have even reasonable form when it comes to how they treat customers, ipso facto, same goes for their data. Expecting entities such as Google, AWS and Microsoft to still be around and remain in their current corporate form in 20, 30 or so years let alone 50 or more is just fanciful. Cloud storage thus requires users to be vigilant and to constantly monitor how their data is being managed on a regular basis. For some users this won't be possible.

This begs the question about the long-term management of say important historical data and such that doesn't have a specific owner or custodian to look after it on a regular basis. As sure as eggs, even if these entities last the distance—which is doubtful—they're very unlikely going to protect this 'orphaned' data as a mother would protect a child. One only has to look at the ruthless tactics that Big Tech has already adopted to see that one's data isn't always secure. Then there's DRM, there's not even any short-term guarantee that data one's actually paid for won't be summarily deleted at a whim.

Now consider the tech itself. Hard disks have a magnetic remanence problem where magnetic intensity drops by a significant percentage per year, thus data stored on them has a definite lifespan. Even if drives are properly archived and only used for data retrieval data rot will eventually claim its data. As stated, to avoid this problem data must be refreshed periodically, even then there are no guarantees that this will occur in a timely manner across the life of the data.

Similarly with SSDs. The way SSDs store data can, at best, only be described as unreliable and fraught with risk. In my opinion, storing electric charges in 'glass'-like medium/substrates and expecting them to remain there indefinitely is like believing in fairyland. As it is, data on SSDs must be refreshed periodically to ensure it doesn't altogether disappear. By nature, electronic data is already ephemeral, so storing it on SSDs then forgetting about it has to be the riskiest of risky procedures. It's almost equivalent to erasing one's data.

In summary, with current technologies, unless great care is taken to manage users' data and to ensure it's refreshed at proper intervals then it will definitely atrophy over time. This is the perennial problem with current storage tech.

Is there the possibility that we'll get almost bullet-proof storage technologies that last indefinitely? Yes, there definitely is and there are some good contenders, but don't hold your breath, there's no indication that they'll be around anytime soon. That said, I'm not even going to mention them here as that'd likely double the length of this post.