This is actually completely true. I'm friends with a guy who owns a surf shop in one of the highest grossing areas for surfing equipment/clothing in southern california, his biggest gripe with the industry is that surfers spend no money. They won't pay for parking, won't pay for surf apps, won't buy a new board unless they have to, don't really buy the clothes, etc. It's part of the culture.
Edit:
To add to his perspective, it's not about getting wealthy from surfing. The guy has been surfing his whole life, is a lifelong lifeguard, surfs 20 foot waves.
He just wishes the industry could grow and innovate, but instead sees it stagnate. Sure the vibe and love for surfing is there, but I think he is frustrated that there is no wealth in the industry to foster further growth and investment.
But then again, the way I see it is surfing as a sport is extremely limited, you can only do it on coasts, and only some coasts are actually consistently good for it.