IBM is the undisputed king of backward compatibility. There is code running on mainframes right now that is going on 50 years old. Microsoft is a close #2 with windows.

I'd probably consider using IBM if it wasn't so goddamn weird and expensive. I suppose all that backward compatibility does have its downsides. Windows feels a bit weird in some places too, but at the same time it didn't start out life as a typewriter.

>Windows feels a bit weird in some places too

Windows 11 still has some dialogs that haven't been touched (and they can't ever be, in order to prevent backward compatibility breakage) since Windows 3.1: https://www.windowsonwindows.com/forum/viewtopic.php?t=44