We would need to define "famous", because just because someone has a steady cam doesn't mean they're famous :P I would think the amount of "famous" "influencers" making that much is a much higher percentage.

Outside of that Twitch leak some years ago, is there any reliable data on how much content creators make?

Small relative to the number of total influencers maybe, but I'm not sure it's a small number in absolute terms. There are an estimated 12 million full time influencers in the US, and approximately 1% of them have 100k+ followers. That means 120k people likely are making 6 figures at a minimum. Influencers with smaller audiences can still make significant income depending on engagement, sponsorship, demographic, hours worked, and platforms they are operating on.