I'd be curious about the COVID impact on recent numbers though - I imagine sellers of physical games that require physical groups of players will have suffered badly compared to online/remote stuff.
My statement about the low earnings of SJG's RPGs and higher earnings of Munchkin is based on their reports, and statements by staffing,
for the past 15 years. For the past five years or so, their flagship RPG has
one full-time employee who can barely afford a shared apartment in Montreal.
Playing RPGs over video or audio chat was popular 15 years ago, and it exploded since. Critical Role is one of the many podcasts and vlogs of people playing tabletop RPGs together.
Edit: I know several other small RPG companies which are one or two people plus contract workers such as
Gaming Ballistic and the Taylor Corporation. I think game designers today are often 'migrant workers,' working on a roleplaying game full-time for six months or a year then moving on to something else then coming back after a few years to write some adventure modules or a splatbook.