> By "computer" I meant "personal computer"

It's not 1992 any more. At the very minimum, it's reasonable to assume that "computer" also includes mobile devices and servers, two additional markets that are well-known to both technical and lay audiences.

> I presume that everybody here would understand that I didn't mean "device which can compute", i.e. all servers, cash registers, calculators, difference engines and Turing machines.

You haven't shown that you know what an MMU is. There's a reason I included that; the definition excludes microcontrollers, devices that lack external memory, and other things that clearly cannot run Windows or any other competing operating system. Most of the devices you mention either don't have CPUs or the CPUs they have don't have MMUs, and they're not part of the Windows addressable market. Since you brought up Windows in the first place, doesn't it make sense to limit ourselves to the general classes of computer on which Windows could conceivably run?

> This is ignoring the manufacturing, supply chain management, distribution, retail competences that the other mentioned companies have, which Google and Facebook may never have.

I didn't mention either company. Both are advertising companies; Facebook doesn't make any kind of product that competes with Windows, and Google's competitor (Android) isn't really its own anyway, as the actual OS is Linux.

> Not all companies will do this successfully, but the companies mentioned will.

I'm not sure why you're going off on me. I explicitly said that Microsoft is likely to remain in business and making money for a very long time. In case it isn't obvious, making money and successful are the same thing. A company can make money serving niche markets, and many do.

> the fundamentals of each business

Microsoft's top product by both revenue and profit is Windows. Windows has a leading market share on only a single class of device (desktops and laptops), and that market itself has been consistently shrinking in each of the last several years (2013: http://b-i.forbesimg.com/anthonykosner/files/2013/04/ChartOf... 2014: http://www.engadget.com/2014/10/08/pc-market-share-q3-2014/ 2015: http://www.gartner.com/newsroom/id/3090817). Forecasts are for continued shrinkage of that market. I don't think it's fair or prudent to ignore those fundamentals, as they clearly are central to Microsoft's ability to make money. Azure may be doing well and may even grow into a strong #2 in its space, but it's still less than 10% the size of the market leader and it generated well under a billion dollars of revenue last year (http://www.forbes.com/sites/louiscolumbus/2015/04/15/sizing-...), accounting for less than 1% (http://www.google.com/finance?q=NASDAQ%3AMSFT&fstype=ii&ei=R...) of the company's total turnover. It's difficult to know if it was profitable, but it hardly matters; the operation is barely even material to the company as a whole. Azure would need to double in size 4 more times to account for 10% of Microsoft's revenue.

Again: I didn't say Microsoft is going to go out of business tomorrow. Or next year or even in 2025. But you should acknowledge that a backward-looking view of the company is risky, and that an objective forward-looking assessment of its business is less rosy than you would make it out to be. At best, the company will be much less dominant than it was in the 90s.

> I mean to suggest that these companies are in trouble because of OSS such as MongoDB

I didn't. As I said, there's a lot of stupidity here. There probably are some small e-commerce and ad companies using Mongo that should be using Postgres or MySQL or Oracle or Microsoft SQL Server, but I don't know that those companies would have gone into business at all if they had to pay an enterprise software vendor for database licenses. I agree that the impact of MongoDB on the named companies' bottom lines has been negligible, and that no evidence of such impact has been offered.

The author and many of the comments here have strayed well into hyperbole, probably fueled in part by ignorance and in part by schadenfreude and glee at seeing some poorly-managed companies in mature markets struggling to remain successful (HP is, after all, the poster child for mismanagement in this space). I don't believe I've made the same error. If you think I have, please provide supporting evidence, as I have provided for my position.