I can understand that but he's not doing that in a vacuum, that's the horrendous problem in using him as an example base rules or what is a reasonable target for the average gm with an average table. The average player is not a skilled actor with a strong financial incentive to make it work while giving back relevant improv that the gm can work off with the expectation of eager collaboration.
You brought up Mercer as a GM who "does a good job of making combats in 5E feel very tactical and using terrain", but he's a useless comparison because almost zero GMs can expect to hta table of skilled professional voice actors like him.
You mentioned players doing a bunch of things in various situations and biting a bunch of hooks, that's better than most references to him that don't even mention the players and just hold him up as some kind of default gold standard.... But you didn't mention the relevant professional training his players have, their financial incentive, or the hooks they gave him back in the moment and between sessions.