I think automation will change the game though. Because the variance that comes from the human factor will be gone. If one chain is a tiny bit better, then every single restaurant will be a tiny bit better. The 0.05% advantage will not drown in the random noise of good and bad employees. And policy updates can happen immediately, the lag from having to retrain will not be there.

One source of variance that will remain is location. The local branch of Very-Slightly-Better-Chain may be poorly situated, which could put them at a disadvantage.