I'd argue that of any software project on the planet, Windows is the closest to having unlimited resources; especially when you consider the number of Windows customers for whom backwards compatibility is the #1 feature on the box.

And speed isn't the only metric that matters; having both the 32-bit and 64-bit versions of DLLs uses a non-trivial (to some people) amount of disk space, bandwidth, complexity, etc.

>Windows does it.

Yeah, didn't say it's impossible. I said it's a tradeoff.

Windows does it and pays for it with slower releases, more engineers, bugs, strange interaction between old and new, several layers of UI and API code for devs to decode and for users to be confused with, less ability to move to new paradigms (why would devs bother if the old work), 2 versions of libs loaded (32/64 bit), and several other ways besides...

E.g. I've stopped using Windows for a decade or so, but I read of the 3 (4?) settings panels it has, the modern, the Vista style, the XP style, and so on, with some options in one, the others in the other (if you click some "advanced" menu, etc).

I have heard a lot of complaints about the costs to the Windows ecosystem caused by having to always maintain backwards compatibility.

Fuck no. A bit faster does not mean fast. It's slow as fuck basically across the board.