No, no, no. I have been talking about source level API, not ABI! This is about developers, not users.
I don't expect the same binary to literally work between all Windows or Linux versions (although in many cases it does, but I don't view that as necessary or even useful).
Plus, I am not disputing the usefullness of open source at all. After all, that's a big part of why I am using Linux. I am just saying that a stable kernel API would make life easier for most developers and businesses.
We should take the good stuff from Windows (stable API), improve it (make it source-only instead of binary ABI) and apply it to Linux.