You are speaking as if you were in the room, as the deals were being signed. Your assertions of what MS "can and cannot do" are hearsay, and I am basing my conjecture on standard operating procedures.
I don't know how to respond other than I think you are wrong. To believe what you are saying, one would have to completely pretend as if the gaming industry was not rife with secrecy. These "unnanounced plans" did not just concern themselves, but their partners. Also, lots not pretend that within 48 hours, they did not publicly state that they would be announcing their plans next week. Why is it so hard to rectify the idea that they would address these at this showing? It makes more sense then playing rumor whack' a mole.
I feel bewildered having to again explain my view point regarding why they wouldn't choose to shoot down the rumours piecemeal. It is obviously a waste of time, so I'm not. I believe my earlier explanation is sufficient.
While MS sending a clear message, right when things started to turn, would have been advantageous for them, this can only be argued in HINDSIGHT. I dont think anyone could have predicted that within a couple of days, Starfield coming to PS5 (which could be still true, but not ready for announcement) would have turned into "MS is bringing every game to PS", MS is leaving the console business ", "MS diddled Nintendo's Wii". It seems to me as if you believe MS should have been able to foretell that one rumor would lead to another, and then another, and another. If this is true, I would love to know where you keep your crystal ball.