It will self implode. This aggressive campaigning to get people in the door for cheap but without any real need to stick around consistently means that people will just jump in and out for major releases. Major releases are not really a Microsoft priority. A few sequels to their 3-4 1st party games will not have enough to draw people during their months and months of down time. Increasing their 1st party, with their new studio purchases and whatnot, won't guarantee them anything if the new initiatives are flops.
Retail suffers since the incentive is to pay way less for access to more games. Digital will too, in the same manner, if it's on Gamepass. They can tank this with their 1st party, but MTX's will continue to be heavily pushed in them, regardless of the PR. Buuuuut I think this is why it'll be few and far between as far as 3rd party efforts coming directly to Gamepass, unless the games themselves are neutered and then MTX'd to death which would spell terrible PR for those companies, and they don't have the Microsoft bag to fall back on.
To be honest it just seems like they are planning a way to exit the console space and just be a pure service a la' Netflix. Netflix does not need to produce hardware, they just need to be on every available device everywhere. Even then Netflix isn't the most profitable and they take a huge loss on their risk/reward ratio creating their own shows. Hence why they've reevaluated more recently. Microsoft has more money to throw around, but they're previous hesitation in banking on their 1st party efforts makes me hugely reticent on assuming they have completely changed. Aggressively expanding and acquiring now, doesn't mean it's going to pay off. And if it doesn't, closures and cancellations will continue to be their norm.
It just seems like a huge, pointless, money sink for their current business model, with a hopefully ROI possiblity potential strictly based on the goodwill of a customer remaining on the service. People are willing to switch and/or completely drop services with the blink of an eye. I just don't see it being sustainable.