They don't make the big chunk money off first party games.
I will get the % for you but its in theory largely 3rd party game sales and more importantly dlc/mtx. There could be a point and a calculation that pc and Xbox is cutting into dlc/mtx more than the loss from sacrificing first party sales.
"They don't make the big chunk money off first party games" because there's A LOT more 3rd party games that come out every week than huge AAA blockbusters that are 1st party. And let's not mention F2P games like Fortnite, where almost 50% of revenue comes from Playstation.
I can assure you Sony itself makes a lot more money with a 1st party AAA title than with a 3rd party AAA title on their platform, obviously. They just release a lot less 1st party games every year like every other console manufacturer.
Sony invests on their games, so that's what my original post was about. They spend their own money on developing, producing, distributing and marketing them. That's the games they want to not only break even but also turn into hits. And they can do that with their current business model. Not by having their games releasing on their 5 dollar monthly subscription service where you can also play 800 other games.
Imagine Sony releasing Horizon Forbidden West, Gran Turismo 7 and God of War Ragnarok day one on PS Plus...back to back like that. Games that cost 100M to develop, plus marketing costs. That would be suicide for all those studios. 50M subscribers aren't nearly enough to cover all the losses and Sony will never spend the same money as MS is on Gamepass to develop their own solution.
My guess? They will bet on previous generations of games, backwards compatibility, adding other stuff like Crunchyroll, Apple TV (possibly), etc to add value to their own thing...and one day if their PS Plus subscription hits something like 100M subscribers they MIGHT start testing that and releasing huge AAA titles there. F2P multiplayer games might have some perks if you have a PS Plus subscription as well to push for a few more subs...but that's it.
Just my 2 cents.