They put games into ‘maintenance’ mode when they realize they need to move on from it. Here is a similar press release for their MOBA from about last year:

https://news.blizzard.com/en-gb/blizzard/22833558/heroes-of-...

They’ve gotten pretty corporate to be honest since Activision took over.

Anyway, seems like the main focus going forward will be Diablo 4, Overwatch 2 and WoW expansions.