This. Many can soi-disant influencers attract sponsorship dollars, but some research we did in indexing Amazon links in product reviews is that the real earnings are in commissions resulting from consumer purchases.

Right, I'm not even talking about other revenue streams. In other words, what % of content creators on YouTube earn more than $10k/yr, even including other revenue sources? I bet it's less than 3.5%.

Yep. Although I would say the numbers (in % succeeding and in the absolute $ of their success) is much higher outside the walled garden of YouTube. You've got strong affiliate marketing programs, you've got retargeting ad companies, you have "sponsored editorial" copywriting, you have VSCO, etc. Overall the world of "advertising" is probably better than it's ever been. Every time I see a traditional 30 second TV spot these days (rare) it's like a flashback to the early 90s.