Microsoft's backward compatibility was always impressive until Windows 10 (ignoring the death of 16-bit on 64-bit Windows). S Mode and the store are great examples of how Microsoft has lost interest in supporting third-party binaries. They want to own Android, not Windows.
I've had software break in the forced feature upgrades of 10, and I had BSODs when printing on every machine I supported at work thanks to a security patch.
It's possible they're breaking some stuff so other things work better. A lot of developers are still using the registry, for example. The choice is basically leave it wide open for developers to break or push them to AppData and friends. All the programs I use also use the current standard, and I don't have any issues.
This might actually explain why 10 and 11 have been the most flawless experience I've had with Windows while so many people have endless trouble. It might be similar to the transition to NT in XP: everything broke, but almost everything made after was more stable and secure.
A much different kind of backward compatibility would have been needed for it to have been more useful instead of unnecesarily wasteful.
Each version of Windows was designed to ideally trigger a purchase of new hardware as a concession to the hardware partners, while each purchase of more powerful hardware was designed to be prohibitively difficult for users to operate using previous Windows versions, triggering a new OS purchase.
Non-Microsoft software suffers more from this disadvantage, compared to the benefit of having some of the Microsoft non-OS software function fairly well across a few OS versions.
I understand how embarassing it would be for users in general to have become aware of how much higher performance they could have gotten from using a previous version of Windows on the next generation of hardware, so this was always made unnecessarily difficult if not impossible.
Also how much hardware could have been saved from scrap heaps if maximum utilization of hardware was given top priority?
When the main reason for growth in manufacturing was consumers purchasing their first computer, this is not as much of a problem.
Once computers are ubiquitous, each new purchase triggers a corresponding waste declaration event.
Accelerating growth pressure under these conditions, while failing to even provide archives for "outdated" code needed to operate remaining vintage hardware, amounts to an overall anti-reuse/anti-recycling strategy.
That's the one thing I've never seen someone accuse Microsoft of. They're famous for their obsession with backward compatibility.
It sounds like you've had a different experience, and now I'm curious. Care to share?