I don’t think bringing up competition is even relevant. All I’m talking about is expectation of one’s performance. There’s definitely an expertise to gaming just as their is in diving. Nobody’s gonna start out as good as Matt Mercer any more than they will as good as Greg Louganis in their respective events.
Forgive me if this has already been talked about as I haven't read the whole thread, but my only issue with this is that Mercer represents a specific style of DMing and gaming, and one that shouldn't be considered as the singular archetype of how D&D "should" be played (I'd imagine that Mercer would strongly agree with me on this point). There are a variety of styles--really as many as there are tables, although I suppose you could narrow it down to a handful of archetypes.
But my point is that Mercer represents a specific style done well, with the benefit of a dramatic skill-set that the vast majority simply do not have. If it is viewed as the way to play D&D, a lot of folks will feel like they always come up short. But if people are encouraged to develop their own style and approach, then budding DMs can find their own brand of success. This kind of encouragement is not on Mercer, but on WotC and the overall community--meaning, us.