Imagine: On Xbox you get Diablo V, World of Warcraft, Starcraft 3, Call of Duty, Elder Scrolls 6, Halo Infinite 2 (etc) for $15 per month, with the 'buy in' price for access at $49, $99, $249 & $499 price points depending on the graphical fidelity you are looking for, with some additional 3rd party hits included as well, and others available at full retail..
...while on Playstation your buy-in to play those games starts at $349, and those games are only available individually for $60~$70 each (or whatever full priced games cost these days).
You go Playstation and buy a couple of those games at full price, Xbox games publishing wins.. profit from sales of multiple full price games.
You go Gamepass on PC to get the games.. Xbox wins.. a new sub.
You buy an Xbox controller and use your built in game-pass app on your tv to access gamepass.. Xbox wins.. a new sub.
You buy an Xbox dongle, handheld, series s, or series x and subscribe to gamepass.. Xbox wins.
You buy additional third party games on Xbox.. Xbox wins (30% of the sale price at very little cost).
Final piece of the puzzle.. you let Gamepass on Playstation only when Sony allows its own service and games on Xbox, thus making the whole scenario moot.
So long as Gamepass offers significant value, and is seen as a near gaming *must have* if one is interested in more than just a couple of Microsoft published games, it begins to make sense. And even if it doesn't to you, and you buy a Playstation and then go on to buy their games for it, they haven't *lost* value from the perspective of their acquisitions.