Well as suspected no actual PS+ totals revealed.
One thing that has me puzzled is how Sony makes it work. For $50 you get an insane amount of digital content.
i think it's just the pure amount of money and not from every single person. as example, let's say sony has 10 million people paying for that only because of this content and they get maybe 30 dollars on average per year, that would make 300 million. if they would now give every developer putting the game on psn "for free" 1 million, that could be enough for many (it's not as if many of those people would still buy those games so there isn't much loss to expect for those games saleswise)
now those numbers are just an example and will be super wrong but it should make clear how it could work. sony could still make money with it even if they have to pay many developers a lot of money for all games together. and they will probably also sell some consoles with this system and take them away from potential xbox/wii u customers.
it's like those humble bundles or something, the amount of buyers/subscribers is where the money comes from for sony and the developers.