Nailed wrong appendage
I think you nailed it spot on there.
Windows was built on top of DOS for a long time and included far too much legacy stuff for far too long. Sure you upset some people by dropping legacy support but it makes for better software for the majority in the long run.
As with the original post, this just isn't so.
DOS was the foundation for Windows until NT came along...Win2000, XP are all derived from an all new code base. But MS kept the APIs supported from the first versions of Windows (Win16s) on the new codebase. Through virtualization, DOS apps also run, even though XP and Vista have no DOS code.
Backwards compatibility through virtualization hurts nothing. It doesn't impact stability one bit. Windows is a mess because of things it chose NOT to virtualize but run natively on the NT base, like older variants of the Win APIs. Those do nasty things.
Retaining Classic in a virtual environment would have made lots of old timer Mac users happy without affecting stability at all, just like DOS virtualization under NT variants. Virtual is safe, and stable. Killing Classic was just an arrogant move without no good reason behind it. MacOS X gained absolutely nothing from it, though slavish Apple defenders like to pretend otherwise.
In contrast, backwards compatibility with older natively supported APIs (which not a single Classic app was) can be precarious. While dropping PowerPC and Carbon support probably will improve MacOS X on Intel (unlike the move to drop Classic, which helped nothing at all at a technical level), it will piss a lot of people off.
But Apple is on a roll and is selling computer hands over fists. Methinks they will take that risk, since planned obsolescence is after all their plan of record for the last several years anyway. And while heartless and a very bad idea from an user support point of view, at least this time there really is a technical advantage to doing so, unlike the pointless dropping of Classic which achieved absolutely nothing given it was virtualized to begin with.