Exe is exactly what I think of when I think of bitrot though. None of the games from my childhood can run on a modern OS.
If you're running js or python etc, even if the interpreters are no longer widely available in the future, people using your code can still try to port it themselves (instead of demanding that you support them throughout the eons).
For Win32 pretty much anything can be made to work with Windows' own compatibility settings, dgVoodoo2 (for games) and minor tweaks. I have many applications and games from the 90s and 2000s, both in digital and physical form and the only issue i face to make them run in modern Windows 10 is the DRM some games in the mid-2000s had (i avoid anything with DRM nowadays).
For 16bit Windows on 64bit OTVDM (https://github.com/otya128/OTVDM) should make most stuff work (especially games). This is also great for installers.
For DOS, DOSBox for games and vDos for applications should run pretty much anything better than when they were new. DOSBox also works if you have Windows 3.1 installed. Yeah these aren't exactly native (vDos does try to use some OS services though) but the UX is pretty much the same with what you'd get even back in the 16bit Windows days when trying to run a DOS application.
I have never had something not work and then work after running in compatibility mode.
When I've (had to use Windows and) had reason to try it, I've tried every OS in the list and ended up thinking it's just a dummy wrapper that doesn't do anything included to make you feel better about Windows but think the program really is a lost cause after all.
I don't think that's within the time horizons that OP is trying to consider. That's kind of like saying "no one (or very few people with great effort) can read the books that we wrote in the middle ages!"
Low maintenance simply means they can afford to give a few months to shut down a service rather than the next day.