Could Larian make an action-RPG BG3? Sure, but why would they want to? DOS2 was more popular than PoE2 or Kingmaker, and the XCOM reboot and games like Fire Emblem are doing great as well, so there is definitely an audience for turn based tactical games.
Except for that you have ZERO evidence that it was the TB aspect of D:OS2 that made it "more popular" than those other games. It could've been so many other factors.
