I think it depends on your skillset and goals. If you want to run other peoples' software and compilers and whatnot, it doesn't hurt to implement to an existing spec. If you're going to write your own or need a lot of mods, may as well roll your own architecture.
If you have the manpower to push support for the foundations upstream, the rest falls into place.
Open Source code can just be recompiled, there is a lot less arch specific hackery going on these days (and if there is for ASM optimized hot paths, it's only compiled for that arch).
Nah it's much easier to move fast if you don't rely on a committee.
I think it depends on your skillset and goals. If you want to run other peoples' software and compilers and whatnot, it doesn't hurt to implement to an existing spec. If you're going to write your own or need a lot of mods, may as well roll your own architecture.
If you have the manpower to push support for the foundations upstream, the rest falls into place. Open Source code can just be recompiled, there is a lot less arch specific hackery going on these days (and if there is for ASM optimized hot paths, it's only compiled for that arch).