I don't know how common it is but it's certainly not dead, it's a staple of Mario games and lately I've been playing Returnal which has some fucking rad dynamic music.

Anyway my answer is "not being a walled garden." I appreciate having official servers that don't suck ass and matchmaking and meticulous balance and stuff like that, but I'll trade it all in a heartbeat for a server browser full of 900 ping russian hosts and easy-to-mod json/xml files.