Going down? No, not at all. Too much money on the table. Shift in strategy though away from complete exclusives and into a timed exclusive mentality? Absolutly.
The problem here is Microsoft is entering a very bad period for Xbox branded hardware. Going multiplatform, even if just for certain titles via timed exclusives, is going to absolutely destroy the Xbox hardware division longterm, as why would most people buy an xbox console over a Playstation if all the big games will be coming to PS eventually.
Do I think there will be another Xbox generation? Yes. Do I think Xbox is in the worse shape its ever been in though? Yes, and I think its going to get worse, and this whole multiplatfom thing is MS seeing the potential end and hedging its bets. There is still a chance things turn around, but the leadership of MS is making sure they are ready for if doesnt.
Long term I think MS wants to be a software/cloud provider who has 3rd parties make hardware (streaming devices) for a full cloud driven ecosystem. I think they want out of the dedicated hardware business but can't pull out fast without destroying the whole gaming brand and losing major mindshare. So its going to be slow, and this is the first big inflection point. I think they've known this for awhile and its why Gamepass even exist, and why they wanted Activision, they needed big players under their umbrella to force the games into their vision, otherwise all these devs would just jump to be primary Sony 3rd party partners.
I think there will be one more xbox generation though as I think they want to set a hardware baseline for future titles with one last dedicated device. After that I image it slowly walks away from hardware, you'll see more and more ads/marketing about MS games/services and less and less about dedicated hardware, to the point where the service of GamePass will be what is talked about when talking about MS Games. We're already seeing that in some regards. Passed that I have no idea what could happen, I've been a big advocate that the whole industry needs to be shaken to its core and the AAA market reset. I think that may be happening right now in realtime, but not because of MS's moves, rather just the cost of AAA games has gotten so crazy high its reaching a destructive point for all participants (though we are seeing that in lots of industries, not just games, the world is very out of balance right now.)