GTA Online will probably be used even if GTA 6 was released. Their multiplayer is constantly being updated, I doubt they'd make another multiplayer version just because of a new game?Even if GTA 6 were announced today (Oct 1,2018), I guarantee it wouldn't be released until mid-2020. The current GTA5 is still thriving and still selling at it's $60 peak with many players still active on multiplayer. But I wouldn't see GTA6 announcement, much less the release until E3 2019 at the earliest.
Yeah their multiplayer will consistently be updated for the foreseeable future, and I see no reason for them to release GTA6 when the previous model is still doing so well. I don't see a GTA6 release until after mid-2020 when the new consoles could be released or announced. So I guess we'll just have to wait and see what Rockstar wants to do with the release of RDR2.GTA Online will probably be used even if GTA 6 was released. Their multiplayer is constantly being updated, I doubt they'd make another multiplayer version just because of a new game?
Would be nice to see another story mode though.