That "trend" has been in progress for a very long time, as electronics aren't repaired but replaced - or rather it was modulelized so instead of focusing on single components you focus on a whole section. It either works or doesn't - and when faulty you replace the whole module. We've done that with computers since the IBM PC.

The reason/motivation was cost. It is very expensive for the consumer to have a subject matter expert in electronics or mechanics do full diagnosis. It's like hiring a programmer to fix your off the shelf software - it isn't cheap and for consumers now that there is a choice, why would they want to pay hundreds of $$$ to replace a cheap cap? It's not the cost of the component that they're charged after all. That too can be applied to cars - after all modern cars are computers on wheels more than they are mechanical. The mechanic only need to be taught how to use a computer to diagnose the car, and be told what part/module needs to be replaced. It's faster and because it's lower skilled it's cheaper per hour too.

This is speaking from someone in the IT field - been there since the beginning of the PC era. We don't really expect code, or make code, to be analyzed line by line. It's modular, full of dependencies and very fluent. To improve code, we often replace whole modules instead of rewriting our code - new libraries, new frameworks is a much faster and cheaper way to improve code, than rewriting it from scratch or attempting to find a way to optimize 10s of thousands of code lines. Only the factory has the experts that design those modules. With computers, the stuff created has a very short life-span - it's often more about "good enough" vs "best/perfect" as tomorrow will have the fixes "automagicly".

As a consequence, the field is much larger than it would be if only the real experts could take part. Imagine the skill set someone doing mainframe programming in the 1940s and 1950ies had to have compared with a programmer today. It's worlds apart. It would be more surprising if other fields hadn't moved towards the same idea. The vast amount of programmers today don't even know how the computer works internally.

I agree with the OP - generally the quality is way down. Does anyone really expect their TV, Blueray player or computer to last for 10 years? You probably already noticed that Blueray isn't really in demand these days - it lasted less than 10 years! The consumer electronics market moves way too fast to be betting on longevity.

Now, speaking as an engineer who likes to tinker with things, like to understand how things work, I do regret this movement. But I have to ask myself if we would have had the progress we've had in electronics if we hadn't focused on making it affordable to the masses. Ask yourself how many TVs would be sold at $8000 instead of Wallmart's $200 made in China, undocumented and often you're unable to find the exact same model after just a few months. But it's cheap - which is why there's a market for it.

So I do not foresee this change back. Not unless the general public gets massively increased purchase power. I'm not surprised the commuter earning $50k/year would prefer this car shop-bill for maintenance isn't in the $1000s but in the low $100s and even that is considered high by many. Recall that in the US more than 50% cannot find enough savings for a $1000 emergency - so it's not buying to save 5 years from now. It's all about the now (even though we all know it's more expensive in the long run). And to lower cost it's modular and "automated" without the need for expensive experts spending hours/days diagnosing to find the exact part that failed.