While not a fan of the Chibnall era. it's worth noting that the BBC identified him as the next showrunner quite early on, and seemed very wedding to him taking over from Moffat, to the extent that they encouraged Moffat to keep running the show long after he might have left because Chibnall had wanted a break after finishing Broadchurch. Given at times Chibnall seemed to give the impression he wasn't that thrilled at taking over you do have to wonder if, again, there was an element of "well if you won't do it, Chris, we might have to let the show take a break."
I'm completely hypothesising of course and may be completely off base! But I've certainly never got the kind of enthusiasm from Chibbers that I got from Davies or Moffat but that might simply be down to him have a less effusive character.