I agree with you on the first part. The previous MS deals while bad due to general contraction of the publisher scene was OK due to how on risk the studios tended to be. Bethesda was more the situation of Zenimax wanting to cash out and win as much as possible (as seen also with the PS5 exclusives).I was fine with MS buying studios like Obsidian, Double Fine, and Ninja Theory, cuz all those places seemed like they were one unfortunate game away from death's door.
But this Bethesda deal seemed unnecessary. As it is, with Phil at the helm, and MS releasing games on Steam, it doesn't personally affect me, but I would guess Phil's got less than 5 years as head of Xbox (by his own accord) and who knows what the next regime will do.
Regarding that, I guess Valve has 5 years tops to get Gamepass (or equivalent) in Steam to become more of a needed part of MS future.