The thing also is that this is likely just the initial wave of restructuring. They'll do more almost certainly as they merge and realign everything into operations as a whole.
And this, of course, is assuming nothing unexpectedly impacts their current plans and direction. If performance dips for any reason its not reasonable to expect them to just carry on regardless, running a service-based business like Xcloud/GamePass is by its very nature dynamic. If, for example, a studio is spending a lot of money to produce titles that aren't moving the needle then they inevitably will intervene in some fashion.
One of the most concerning aspects of things like GamePass is that KPI's aren't necessarily obvious. Yes, you can look at overall subscriber count, retention, engagement, supplementary spend, etc. But the actual figures for both performance (P&L) and expectation per studio/unit are not going to be easily verifiable by external sources - front facing communication is always going to be filtered through a PR lens. Upshot being that if the top brass aren't happy with a certain team, its likely that the first time there's any indication of this is when they are downsized, merged, or disbanded.
Its pretty much inevitable in my opinion that this is going to happen sooner or later, because its a totally normal thing for corporations to regularly review performance for entities under their remit. Phil Spencer might offer a longer leash to certain studios and properties, but they'll never get free-reign forever! Because if he did, he wouldn't be in the position he is as its totally antithetical to corporate business practices.