I don't care.

Started doing desktop software development on MS-DOS 3.3.

POSIX is only relevant for C, the bits that they felt shouldn't be part of ANSI C, not to impose UNIX semantics on other OSes.

It is completly irrelevant on programming languages with rich runtimes or good package managers available.

Are you saying that the only people who care about POSIX are those saddled with legacy systems that they can't get rid of? That actually sounds about right to me.

They aren't the only ones, but there's some truth there. POSIX, and other similar uniform standards, are very much a "you don't know what you've got 'til it's gone" type of thing.