Well I dunno what some of y'all are talkin' about but for the original question, I don't see how it's hard to contend with the idea that Sony and Nintendo are the premier first-party game creators (or publishers, or producers, or whatever). Talking about proprietary stuff, right?
I mean I feel like "Nintendo" is its own subgenre of games. And it's a subgenre I personally dislike (Bayonetta is the only exclusive franchise I've enjoyed from Nintendo since I got back into gaming as an adult). But that's good, though- like I know it's not for me.
Meanwhile Sony is the THE place to go for third-person action adventure stuff. Spiderman, Last of Us, God of War, Returnal, Demons Souls/Bloodborne.. which is precisely my jam.
Now, because I'm a single dude with disposable income I have all three platforms and they serve different purposes:
Playstation 5: For Sony exclusives and big AAA titles like Elden Ring.
XBox Series S: GamePass box
Nintendo Switch: traveling toy for indies and Bayonetta, to be replaced with a Steam Deck after I'm finished with Bayonetta 3
Microsoft's best thing is Gamepass, not any game because I don't care about Halo.