The more interesting question...
> Why have neither Intel, AMD, ARM or Samsung developed a similar approach
...is why Microsoft *did* do it, only to apparently shut it down "since the research questions have been answered" (by the looks of it, in the positive).
That, along with the last sentence about not upsetting their "silicon partners" reads to me like one important strategic goal of this project would have been precisely to put pressure on those partners by saying, "look, you're not indispensable, in fact we could really upset your boat if we wanted to, so now about those prices..."
PS: I must stress, I am talking from a position of complete ignorance about these things. Take the above more as a question than as any form of assertion.