Re: Redmond's not been super-responsive of late.
"Who really owns your copy of W10 then?"
(Let's assume that we all know that the question is...) "Who really owns your license to use W10 then?"
Basically, anyone who pays for a copy or is granted a copy for having met the conditions for receiving a free copy. That Microsoft can revoke anyone's license on a whim might be enjoyable to write, say, or think, but doesn't have anything to do with events in the real world, where revoking someone's license to use Windows without really, really good reasons will mainly net Microsoft various lawsuits. I can't imagine that it could be done on any basis other than case by case.
This is essentially independent of anything in the EULA - because commerce is commerce and the EULA takes precedence of no laws whatsoever.
Additionally, in spite of anything in the EULA to the contrary, tech companies can not unilaterally, fundamentally, and substantively change the terms and conditions in the EULA. The EULA is (or perhaps it would be better to say "may in fact be") a contract but only insofar as it is binding for both sides. If they can broadly and substantively change the terms and conditions at will, the EULA becomes binding only on the end-user, and therefore can not be a valid contract.
Furthermore, while some terms and conditions in a EULA might be enforceable, others might not. No EULA is 100% enforceable merely in virtue of having been agreed to. Each provision must be enforceable and no provision of a EULA can conflict with the laws of the relevant jurisdictions. (Conversely, invalid clauses in a EULA do not necessarily invalidate the entire EULA.)
Of course, tech companies puts those terms and conditions in the EULA in the hopes that most people will be fooled. And although most people never even read them, there are plenty of people who fall for them. As we see.
https://en.wikipedia.org/wiki/Unconscionability
https://en.wikipedia.org/wiki/Contra_proferentem
https://en.wikipedia.org/wiki/Standard_form_contract
https://en.wikipedia.org/wiki/Illusory_promise
Comic Relief:
http://www.makeuseof.com/tag/10-ridiculous-eula-clauses-agreed/