Sadly, and it certainly isn't from riding a skateboard, but Rob Dyrdek might be the richest. It might be Hawk for the video game royalties and all the bigger sponsorships, but apparently Mtv has accumulatively paid Dyrdek more than any other person. I didn't realize how omnipresent he was until I read this article (from a SLAP link I think):
https://www.theringer.com/tv/2020/9/15/21436802/mtv-ridiculousness-rob-dyrdek-reinventionFor richest from actual skateboard riding, it's Hawk and Stephan.
Props to Janoski for all of his multi-millions from basically just insisting on a simple shoe from Nike back in the day. I like that he was referred to as "Air Pippen". Not even the most accomplished skater on his team (Nike or Habitat) but the obvious winner in the skate shoe game. To think that pros like Ishod are breaking themselves to get a color way of Janoski's shoe, and Tony Hawk, while there is still technically a namesake shoe brand out there for him, is still drifting from shoe sponsor to shoe sponsor over the past decade.
Dill must be getting pretty rich here nowadays too, I imagine.
For poorest, it's a toss-up between hundreds of people. A great swath of sponsored skaters are near (or actually) having a net-worth below zero. I'm sure not anymore, but not too long ago Gonz was deep in debt to the IRS.
Fred Gall, now sober and not presently mooching for IRS payments, with home ownership, full time employment outside of skateboarding, and co-owning a clothing company that probably breaks even, is doing ok. Probably better than most pros.