quarterly reports of MAU for blizz went from 45mil at OW2 launch to 27mil to 26mil and the last one has 10mil diablo 4 players. It may not be dead but it's hemorrhaging players like there's no tomorrow.
Launch quarter for OW2 also had a wow expansion launch but it sounds like it was mostly bought by the smaller, core fanbase who have kept playing. Either way, adding 10mil MAU in Q2 and not being able to get the number above Q1 via a new game does not speak well of their retention.