Nothing will change. There is a mass group of gamers that seem to only move from the newest thing to the next thing. After a month or two we'll see the numbers drop by 50% or so, then more, etc. Being multiplayer will keep things higher than normal, but it won't be hundreds of thousands all the time.
Also, I doubt devs will change much, gamers will still be looking for other games to play, although, rpgs will now be compared to Baldur's Gate 3, at least in the media. When I'm playing Armored Core VI, I most definitely won't be thinking "oh man, if only they did 'x' like BG3", or with Cyberpunk DLC, same thing.
