The only irony is that the one Linux system that is widely successful in the consumer-facing personal computer market is the one that choose to completely abandoned all pretense of POSIX compatibility and traditional linux-distribution approach to packaging software and went with a dedicated Java-based userland.
This pretty much breaks all the rules that most of the *nix pundents on LWN and most other forums consider core requirements for success.
The biggest problem faced by Gnome and other folks if they want to remain compatible with the BSDs and Solaris and be able achieve their goals pretty much means writing their own entire OS that runs in a abstraction layer on top of a POSIX API that runs with enough privileges to aggressively bypass everything the BSD/Solaris kernel does.
That means having their own graphics drivers, own hardware discovery, own INIT system that runs on top of the existing init system, etc etc. All of it isolated and restricted from anything else that may happen on the OS.
It would be far easier and cleaner approach to port OpenBSD to be a Xen host and run Linux/Gnome desktop on top of that.