Im just taking numbers out of my ass here, but i am pretty sure more than half of the rentpass subscribers are there because they want to play cod online and not because they want to rent games..That would be a "boss" move. Like buying Bethesda and getting MLB for GP day one were "boss" moves.
It would kill rentpass. People who want to play latest cod, bf, gta online would choose ps5. No one wants a monthly online bill.