What are you talking about? Linux has virtually no backwards compatibility at all. Maybe one or two years max. The kernel is fine. The weak point is glibc.

You literally need to recompile applications constantly to stay compatible with glibc. Otherwise they just don’t work.

The good news is that distros are constantly providing freshly compiled versions of open source applications.

The bad news is that actual binary backwards compatibility is non existent. Try running a binary compiled in 2005 on modern Linux. You’ll just get a ton of glibc errors.

Windows lets you run applications compiled in 1995 on modern desktops.

Linux is great and it’s what I use. But we can’t claim backwards compatibility as a strength. Maybe a binary compiled today with musl might run in 2036 but musl targeting is quite rare.