It's definitely going to happen. It's way too much of a cash generator for R* and TakeTwo to ignore.
You can't go off that average 4 year cycle, that's not generally how devs like R* work.
They're not the type to rush something out just to keep to an average cycle (looking at you COD).
From what I know, they're more of the "when it's ready" type.
They take their time, build a detailed world over years, and then have a last minute panic as they go gold to rush to remove some code they accidentally left in there.
Nope, you're wrong, they are not "when its ready" type, not anymore atleast. GTA 5 is an unfinished game and it got a lot of downgrades from GTA 4:worse ragdoll, vehicle and weapon physics, bigger but emptier city, only 69 missions in the main campaign, non-existent plot, bad secondary missions like yoga(the guy who implemented it was was having a fu*king co*k in his mouth that day), useless countryside altough its beautiful, bad characters, bad humour, sh*tty cliches and so on...
Online doesnt count since you need an internet connection to play it and its updates dont get added to singleplayer mode.
Best GTA game till date remains San Andreas, with GTA 4 better than GTA 5 anyway.GTA 5 is the worst gta game since the 3d era.
The last great game Rockstar has made was in 2010(RDR), anything post-2010 is overrated garbage like max payne 3, la noire, and like i said, GTA 5
Rockstar isnt a serious company anymore