Why is it on Sony then and not the developer, if that's the "sane" approach? Regardless of knowing the exact roadmap, it was clear that future iterations of PS hardware from the PS4 onward weren't going to delve into more exotic architectures anymore and stick to the more off-the-shelf industry architecture, so why did Sony need to mandate anything about the software design that isn't mandated on the PC side where devs seem to figure it out perfectly well on their own?
On PC side a developer could release anything, including titles that never touch the GPU or do all kinds of "bad" practice. It's an open platform. Sony, however, are operating a closed platform, so they have the opportunity to mandate certain requirements as well as offer support for them in their abstraction layer. So for example, if they knew they were eventually going to offer a platform with an improved GPU or CPU, they could have required that developers do not tie their game logic to the fixed clock speed of the CPU as part of QA. This is already an obvious bad practice on other platforms these developers already support in 99% of cases anyway, so there would have been a minimal trade-off at the start for a big win later (when you can announce that all your titles get improved performance out of the box).
You are misunderstanding how PC's do forward compatibility. Back in the days of DOS, games wrote directly to the hardware and didn't take advantage of new hardware and would often break when new, faster CPU's or GPU's were used. I owned many, many DOS games that broke with new HW. Hence new hardware, often had a backwards compatibility mode.
Microsoft designed Windows to solve that problem by forcing games to use Windows API's (e.g., DirectX) that talk to a device driver that then talks to the hardware. With Windows, Half-Life 1 relies on DirectX and hardware device drivers in order to run at higher resolutions/framerates.
Consoles provide lower level hardware access than Windows and so will never have the same path for forward compatibility.
Modern consoles do the same kind of abstraction as Windows APIs do. They're just a lot more performant at it since they are designed around a specific use case. The jump from DOS -> Windows was a paradigm shift, whereas going from one fixed iteration of an AMD CPU+GPU to a better one shouldn't be causing any major pain in terms of forward compatibility - if the abstraction layer is designed with that in mind.
I should say that in terms of hardware Sony are doing almost everything right in terms of performance/cost - my only issue lies with them not accounting for it so well in software when they have explained that they were planning a hardware refresh since day one.
