Exactly they make much money by selling the console,the game throught they store and the ps plus subscription (the latter it's the reason why they still haven't published GTS on pc since it is an online centric game where there are still a lot of people that renew the psplus subscribtion to race in sport mode) . Putting the game on pc they incentivate people to get out their closed ecosystem where they basically make a lot more money then putting the game on pc where people don't need a subsription to play online and they have to share profits with steam or epic games store since they haven't their own store on pc
An argument that could be used for just about any of the titles Sony has already brought to PC (or is planning to), they are bringing God of War to PC in Jan '22 and that's sold over 19million sold since launch in 2018, and as such has been a much bigger flagship and system seller for the Playstation as a platform.
By not doing a day 1 PC launch, it allows Sony to effectively hit two markets with minimal cannibalization, effectively increasing sales (and therefore profit) with minimal risk of cannibalization (which would exist if you did a day 1 release on both platforms). Horizon Zero Dawn sold over 10 million on Playstation, yet in less than a year has added another 700,000 units on PC (all with no manufacturing costs, physical distribution costs, etc.
Sony seems to think this is a solid enough model that they recently changed the name of the division they publish PS titles to PC under to
Sony PC, and if IP's such as God of War, Horizon Zero Dawn, and
Uncharted can then GT7 arriving in a couple of years time is not as mad an idea as it would have seemed a few years ago.
Uncharted 4 also negates the online argument as well, as GTS has sold circa 10 million units, and around 60% of people have completed the trophy to play sport mode (so around 6 million potential online), while Uncharted has seen 45% of people complete its online tutorial, but with over 15 million units sold that potential is 6.75 million. So roughly comparable in that regard.
I mean it's not as if Sony didn't say exactly what I've just written
“The strategy as we were developing it when I was there was that we need to go out to where these new customers are, these new fans could be. We need to go to where they are because they’ve decided not to come to my house. So I’ve got to go to their house now, and what’s the best way to go to their house? Why not take one of our top-selling games, which has already blown up the marketplace, already been out there for 18 months, 24 months…and bring that to the personal computer platform? Hopefully, with that, people who are not currently inside the universe of PlayStation get a chance to experience what we’re experiencing”,
Layden explained.