Being on YT is a big driver here, and Lex is smart enough to work the algo. Have John Carmack on, get views when people search for Quake. Have Elon on, get subs when people search for Tesla. Have Mr Beast on and get some kids in the funnel. He's very good at piercing through filter bubbles to get extra reach and pull numbers, unlike an Alex Jones. (EDIT: For this, the bland persona is a feature not a bug)
I'd ballpark that he made $20k off this DHH interview and picked up some rails devs along the way.
Whenever new coworkers bring up Lex, I always feel like it's a test, like are they oblivious, or are they secret closet magas trying to test the water. Slate Star has a similar thing. And YT is bad enough but now I have to see it pop up on LinkedIn too.