The problem with POSIX is that they don't work to define the fundamental necessities of a good OS, they merely document the cases where most of the distros have

The problem with POSIX is that they don't work to define the fundamental necessities of a good OS, they merely document the cases where most of the distros have the same functionality with the same syntax. This ends up being only a subset of the typical functionality found on a system. Even worse is the way they can lock in old braindamage and make it harder to fix.