after exclusives, brand is second most important thing I think.
I skipped PS3 gen completely, and PS4 didnt have any interesting launch games and launch year were anemic, yet playstation as strongest gaming brand + good experiences from ps1+2 made it 100% easy to choose ps4
Now Xbox s/x is in the situation where they have also almost non-existent exclusives for launch year/launch + they dont have any brand* compared to PlayStation / Nintendo, I would guess it makes choosing them really difficult (to people whom didnt have ps4 or one).
So, because they are always the underdog because of weak and non-popular brand, launch exclusives are way more important to them than to Sony. At least that is my theory.
* talking from european perspective, xbox is almost non-existent here, I dont recall ever seeing xbox ads on tv, yet even Nintendo spams switch ads currently. It is like MS already gave up here. I even asked from many friends have they seen xbox ads, because I werent sure if it is my biased viewpoint, but nobody had seen any in years if ever.
So, exclusives are super important, especially to Xbox as they lack the power of brand Sony + Nintendo have
15 euro per month vs 80 euro at once for a single game? I know what would I choose.
And owning a game...With the exception of some legendary games - that are must buy like Skyrim or GTA - I don't return to old games at all. I doubt a lot of people do either. You can buy them if needed of course (such option still exists)
But dont people always say how good gamepass is because hundreds of old games that they can play?

So why do you think it is good to pay for games you dont play?
And it is damn worn out argument to say "15e vs 80e" as nobody forces people to pay 80e, right? So, how do you think it is fair comparision?
you also leave out all games that are not in gamepass, so you have to buy them at 70-80e + pay for gamepass, with same logic.
In reality 15x12 = 180€/year. how many games do you play/year from the gamepass? for 180€ it is easy to buy 5-20 games from sales, more than enough for a year. By being smart I mean, and buying used games for -30% to -60% after some days/weeks from launch or waiting for bigger sales.
or, you can pay 80€ and sell it for 50-70€ after you complete it, if you complete games fast and dont return to them like you.
but in the end comparing gamepass to normal games is just stupid, as there are people whom benefit from GP and then there are people whom benefit from buying games, neither is perfect for all.