Getting paid to skateboard exists solely through sponsorship (and I guess some prize money for a select few). So, if a brand's product doesn't sell more based on a association with a skateboarder, there is no incentive for the brand to pay the skateboarder to be associated with it.
This gets really difficult for skate brands that only make money from selling skateboard products and accessories where there is very little money to be made these days. This is why brands like Red Bull or Nike are paying the big dollars... they make huge profits from selling a universally popular product. Board brands sell a niche product and barely make enough revenue to pay a living wage to a pro.
This makes it essential to support the board brands you want to succeed. And, yes, if you do the math these brands make more profit from selling soft goods than hard goods. Not only that, the logos on the shirts and hats promote the brand a lot more than the deck graphics.
I'm continually disappointed by the amount of Adidas and Nike logo clothing I see at the skatepark. Sure, buy the shoes if you like the shoes, but you don't need to promote that brand with every article of clothing. I really don't think a Nike logo hat is a better hat.
With all this in mind, it is easy to see a day coming soon where board brands are more or less a thing of the past. Shoe companies (all 3 of them), energy drink and soda sponsors, and whatever other corporate product decides to enter the sponsorship market will determine the pros since they pay the money. This is also how the Olympics is going to shift things... it will make some skaters household names and give corporations incentive to pay them to rock those logos. Nora is about to get a lot of corporate sponsorship opportunities. One month's check from a brand like Nabisco will be bigger than a year or checks from Welcome. Why ride for Welcome at all (from a financial standpoint)? It will be sad to see professionals decked out in logos like a Nascar car, but we are clearly already headed there.
And seeing here on this SLAP thread how we are all posting how proud we are to not wear board brand logos on our clothing, it is easy to understand why board brands put all their marketing towards a different demographic. We may ridicule Darkstar for being in toy stores, or Revive, but they know they will make more money from Moms than jaded, logo-free middle aged skater men like me.