This is almost certainly false.

As a CTO at largest banks and hedge funds and serial founder of multiple Internet companies, I assure you contracts for novel and "existential" technologies the buyer builds on top of are drafted with rights to the buyer that protect them in event of seller blowing up.

Two of the most common provisions are (a) code escrow w/ perpetual license (you blow up, I keep the source code and rights to continue it) and (b) key person (you fire whoever I did the deal with, that triggers the contract, we get the stuff). Those aren't ownership before blowup, they turn into ownership in the event of anything that costs stability.

I'd argue Satya's public statement on the Friday the news broke ("We have everything we need..."), without breaching confidentiality around actual terms of the agreement, signaled Microsoft has that nature of contract.