Not sure.
Up until last year Game Pass PC was 1 dollar a month the first one and then 3.99.
For the price of one single game bought at launch, you get a year of Game Pass.
Tell me lies, tell me sweet little lies? Seriously i don't see how that can be profitable unless they start increasing the price. Or maybe there's something else we don't know: like they sell data gathered from Game Pass.
I think that's the catch. Both PS4 and Xbox One send data about every single thing you do on the consoles: what games you play, at what time you play, what games you own, how much do you play, your internet speed, your geographical location, your tv resolution, and even the demographics. All that data is far more valuable than any price Microsoft or Sony would charge for their service, and boy do they use it!
Why do you think Google is pushing Stadia (instead of letting it die), Apple is doing something similar to GamePass, and Sony signing an agreement with Microsoft so they could better use all that data?
And that's one of the reasons those companies are pushing gaming in the cloud so hard.