Question is how much longer can GTA/RDR continue to draw a crowd scale wise? Bethesda is in the same boat, same game over and over again, different IP's. There will be a point where GTA can't provide what a player wants because they've reached the limits of the scope and would have to change the game drastically, potentially losing a mass of players in the process.
Let's give an example: What happens when GTA has the entire state/country/ world to drive around in, after that what's next? Can't turn GTA into SC obviously. Fallout and Oblivion are in similar boats but have an opportunity for Death Stranding to continue on, however Bethesda needs to quit with the mile wide inch deep games they make. Games like E:D, NMS and SC are already deep and growing deeper. I think Bethesda is scared to put themselves out there by challenging their own standpoint on how their games are made.