Also: 4.8M/24 people is still 200k per head. Even if you assume that various costs take 50% of the revenue, they're all still making 6 figures for a thing that's pretty much a side hustle for most of them.
Also it started out being a side gig but most of them have switched to it as their primary gig. They are starting campaign 3 this fall.
As a point of comparison, a talented voice actor can gross around $125k per year, working from home as a freelancer. I don't feel that the Critical Roll actors are being overcompensated at all.
The most amazing Critical Role fact might be its creation was indirectly financed by Youtube/Google :o. Felicia Day knew all of those guys and about their private DnD game, she invited them to film few episodes for her YT channel "Geek & Sundry". Channel started with $1Mil advance from YouTube Original Channel Initiative, one of the rare if brief successes.
It's basically a regular job at that point.
If you look at social class stratification, the general assumption is that if you have to work a job for your income, you're not upper class, you're serving in the employment of the upper class. If you have a high paying job, that's defined as "upper middle" social class at least until you have accumulated wealth to transition to a capitalist/owner/investor role (as some popular musicians and athletes do); being in the top 4% of earners is quite reasonable for traditional upper middle class roles e.g. independent lawyers and doctors, which also tend to earn 200k+/year in USA.