Well, it was only a matter of time......
..........when Google would conclude that the tail was wagging the dog from their point of view.
"Today they must be weighing their options – and the daunting cost of creating a joint competing brand to Google's Silver."
In practice it is only Samsung that could do this (i.e. Fork Android and go it alone.). They are probably the only Android OEM with brand name recognition on the scale that would be necessary to take that step. Their "skin" (Touchwiz) is sufficiently "dense" that the visual change for the ordinary consumer would probably not be in any way "jarring" but there is, of course, a fly in that particular brand of ointment. If I may be permitted to quote/paraphrase a exhortation used by one of Bill Clinton's election advisers, "it's the apps, stupid". Indeed, Google Play is Mountain View's not so secret weapon when it comes to maintaining a firm grip on Sammy's organs of generation. As long as you do not have that kind of facility (Amazon was able to do it with its "Fire" range but Amazon has software and content coming out of its ears) you are stuffed.
On a side note, if The Demon Spawn of Redmond, AKA M$ or Windoze (or whatever tired and unimaginative insults you can come up with) had announced plans to do this to their OEMs (or if they were to do so in future), what do you imagine would have been/will be posted on a thread like this one....hmm?