Thats like saying, "if Netflix and other sub-based content providers are good for content owners, why doesn't everyone launch big theatre releases on such services from day one?"
The model for AAA games is to release at full prices and transition to sub-based service when sales die.
The question to ask is, does Game Pass makes sense for publishers once their games are far from release and when their games exist amongst 10,000s of titles receiving minimal marketing at most?
Not, can MS afford to pay me 100s of millions of dollars to put my AAA game on Gamepass at release?
Furthermore, looking at physical sales doesn't tell us much anymore.
Xbox is a more digital distribution-centric platform. It's been heavily pushing gamers to try GamePass for years, thus encouraging everyone to download digital titles. There is nothing that says the behavior of Xbox and Sony gamers is the same when choosing DL over physical.
Go look at best sellers in video games and separate by platform and just games. Both the PS5 and PS4 best-selling skus are dominated by physical titles. The Xbox One doesn't even have a physical title in its top 10 video games. The Xbox Series X/S only has three.
https://www.amazon.com/Best-Sellers-Video-Games-Xbox-One/zgbs/videogames/6469296011
https://www.amazon.com/gp/bestsellers/videogames/20972814011/ref=pd_zg_hrsr_videogames
Ubisoft is one of the few publishers that still breaks down revenue by platform. Last quarter Sony garnered 27% while MS garnered 23%. Last quarter for EA 2/3rds of its full game sales was through DL. Last quarter Activision, consoles were its top platform for revenue at $799 million (out of $2.2 billion), yet retail channels only generated 7% of that revenue. Digital online channels generated 88% of that revenue.
To put this into perspective, RE8 is the second biggest PS5 title in terms of physical sales this year. It still sold 40% fewer physical units than RE7 (a late January release) which was outsold by both RE5 and RE6.