If deep domain knowledge paid off on Youtube people like Ben Eater would be a millionaire from Youtube at this point[0], his videos are so cool and great at explaining computing. Or Clickspring, the guy who made the Antikythera Mechanism [1]. But honestly even for me being a software engineer and someone who considers himself interested in this sort of stuff, I look at these pages sometimes out of wonder but I often end up watching comedy videos and stuff like that on Youtube. The algorithm recommends it, and I watch.
“Exploiting” is the keyword here. You need to exploit the niche. A better example would be someone like 3Blue1Brown. You have to keep at it long enough and keep improving. Go check Grant’s first video and the latest video, the difference is just night and day. On the contrary, although decent in terms of the content, Ben hasn’t improved in ways measureable. When you use these mediums, you are trying to communicate while being engaging. If Ben indeed is providing engaging content that is deep and valuable, and you’re not just extrapolating from n=1(because you learn something from those videos), it should’ve worked out for him , no?
I suspect he's doing fine. Millionaire? Well, of course not, but he is sort of niche.
But he also sells kits and I suspect that's been very useful to his paying for his ISP. I know I bought his 6502 kit. ;-)
I think the smart "content creators" figure out a way to sell plans, etc. in order to take in a little on the side. (Patreon, in my mind, is the worst way to do that.)
It doesn’t require elaborate demos or expensive equipment or deep domain knowledge.
It’s youthful exuberance, some theatrics and the right personality.