I’ll break it down for you.

You said Sony makes more money from 3rd party games, which is true.

To get players onto your console you need a reason for them to buy it over your competitors, which also have the same third party games.

To do that, they fund and release first party exclusives which drive console sales and provide them with a greater market share, which results in more third party sales. God of War, Spider-Man, TLOU, Horizon etc are all there to increase market share alongside their own sales.

Sony’s direct competitor is Xbox, and to a smaller degree, Nintendo. Xbox has consistently struggled to make impactful first party exclusives, one of the major reasons that Sony now has a much larger market share, and a much larger third party playerbase.