It's already quite well known that some Windows XP era games cannot run properly on Windows10. It does not affect every game out there, but it's easy to find enough to say this is a problem.
I recall seeing videos on YouTube of Windows 1.0 applications running on Windows 10, so I suppose it really depends on what type of software exactly; more system-level things like disk defragmenters are unlikely to work, but basic productivity software likely will continue working. I personally have a few from Win95 era which I still use regularly, and of course I'd expect the basic Hello World messagebox binary to remain usable 10 years from now.
I doubt it will be too long before 32-bit versions of Windows are no longer produced or supported. The 64-bit versions do not run 16-bit software. When that time inevitably comes, the Windows 1.0 software will also stop working in native Windows (rather than a 32-bit or even 16-bit Windows version running through emulation).
Basic applications such as that, sure. But the top parent comment referred to games, which are the opposite in terms of complexity and operating system features, and generally harder to support adequately in emulation.
