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Accelerating growth pressure under these conditions, while failing to even provide archives for "outdated" code needed to operate remaining vintage hardware, amounts to an overall anti-reuse/anti-recycling strategy.
