Don't believe I said otherwise.
> This has nothing to do with "whoever is running Windows development these days"
> Microsoft saw the opportunity to kill at least one backward compatibility burden by not even trying to support 16-bit for x64.
These two statements are at odds. Microsoft used to take compatibility extremely seriously. It would have been relatively trivial to allow 16-bit applications to run, and obviously there is desire to do so since WineVDM exists, they just arbitrarily decided not to.
I suspect this is because they've become infected with developers who use Linux a lot and think nothing of breaking compatibility every release, let alone in cases like this.
It didn't exactly run 16-bit installers. https://devblogs.microsoft.com/oldnewthing/20131031-00/?p=27...
Back when 64-bit Windows came out (with XP and Server 20003), the adoption was pretty small since most applications were not 64-bit and did not need 64-bit address spaces. Microsoft saw the opportunity to kill at least one backward compatibility burden by not even trying to support 16-bit for x64. They figured, rightly, that by the time x64 became widespread, 16-bit would be obsolete.