Isn’t backwards compatibility one of the tentpole features of Windows? If you meant future versions of apps, sure, but I’d otherwise not expect this to be a problem in any significant sense.
I’m not sure what you’re arguing here. It’s backwards compatibility if a given version of say, Photoshop, designed to run on Windows N, now runs on Windows N+1 as well… at least from the perspective of the OS, which is what we’re discussing?
It’s forwards compatibility if we’re discussing the idea of the program being compatible with future versions of Windows, but that’s neither the point of what was suggested, nor is it realistic — breaking changes, or compatibility, are going to be at Microsoft’s hands and largely an intentional decision at a platform level, not something an individual developer can shore up against.
Genuinely not trying to move goalposts here, but I feel like games have always been the exception, due in part to their reliance on so many of-the-time technologies, at least for AAA titles. Either way yours is a fair point. I still think the original point broadly holds for more traditional programs though.