That's an interesting take (to me) both as a fan of Critical Role and as a person who relatively recently dove into GMing with very little pre-meditation. In the groups I've played in it has almost exclusively been the older gamers (mid-40s and up) who dislike theater of the mind and prefer having the Dwarven Forge-esque dungeon tiles and pre-fabs and minis and spell effect markers and what-have-you. The younger players seem fine with "OK so there's a grid to judge distances and we have some chess pieces or extra dice or cheetos or candy or whatever to stand in for the monsters. Cool."My concern is Mercer has the opposite effect. I started DMing when I was 11 because DMing in 1981 meant drawing a dungeon on graph paper, populating it with monsters and treasure, and running my friends through it the next day. That was an easy on-ramp to being a DM. And that ease of entry is the reason why millions of kids under the age of 15 played D&D in the 80s.
Today, the expectations of what a DM should bring to the table is so much higher in terms of preparation, system mastery, story, roleplaying, etc. Prospective new DMs seem extremely intimidated at taking on the task.