I can’t think of a single “pro” to not having a variety of content

The issue with variety is that people who want variety don't want the same kind of content. I kinda agree that they do too much TTT, but I also understand why they do it. There's a dedicated audience that watches TTT and it's what gets the biggest and consistent views (so it's what most people like and they return for every episode). Now, there might a bigger audience out there that wants variety, but for one person that means more GTA, but another has no interest in GTA and wants to watch Colony Survival, yet another wants other live action videos, etc... The result is there is that this potential big audience is split up and these other projects will get less views than TTT, because only a certain part of the people who want variety, wanted that specific variety.