For Windows, iOS it seems to be decisions by committee and business need.
You say this as if somehow a committee eliminates the politics that are present in Linux, which cannot be further from the truth. I bet there are tons of things that the committee for each OS has turned down for various reasons, but you and I don't know about it because it isn't open.
Seems like the King does not want something added to "his" kernel,
Precisely right. RH is fully capable of adding it to their kernel, as are any other distros. Linus does not want it in his kernel and that's that!