My experience is that a 20 year old exe file has a greater chance of running in wine than it would in windows, and a 20 year old Linux executable is going to fail because the shared libraries it depends on are unobtainable

In my experience:

20-year-old exe files can fail on both Windows and WINE if they touch something relatively obscure. It's easier to throw files at the problem under WINE though (you can just throw away the prefix if you break something). The single biggest mistake WINE makes is defaulting to a single shared prefix (and the second sin is similar - trying to integrate folders and menus naively).

20-year-old dynamic binaries on Linux can almost always work today; snapshot.debian.org has all the old libraries you'll ever need. The potential exception is if they touch something hardware-ish or that needs exclusive access, but this is still better than the situation on Windows.

20-year-old static binaries on Linux will fail surprisingly often, since there have been changes in filesystem and file layout.

I've got a terminal open on my desktop, running a copy of ZORK from 1983, which is 42 years old.

Yes there are modern ports, and newer versions, but these kind of retro games, and utilities, are used by many.

I use Nikon Scan 4.0.0. It was released in either 2008 or 2004.

You can have an Electron app with the same features, but an older program likely can do it without being Electron or webapp.

Games