Mikey,
Yes, definitely, SBI charged for pit access at the Key West Worlds. (I wasn't there this year, but that's been standard.) But the best viewing areas are in Mallory Square, and the only ones collecting from that gate, if you will, are the bars and restaurants. That's great for them and it's as it should be, but it does nothing to help offshore racers and promoters defray their costs.
I've been to one Powerboat P1 race and one UIM Class 1 race, so I'm not an authority. But what I saw at both were tiered levels of VIP hospitality tents (silver, gold, platinum) that ran from expensive to very expensive. Each hospitality tent had a viewing area outside. However, the majority of the spectators at both events were on the shoreline (no way to charge for or control that) and private boats.
Maryland Mark makes a great point about what I would call critical mass. Certainly, a bigger crowd is going to be easier to sell to a sponsor than a smaller crowd. But high-level sponsors are sophisticated. They want to know, in hard numbers, what their return on investment will be in terms of product sales. And again, who wouldn't? They're looking for simple metrics, and if you want their money you have to be able to provide them.
Sponsors also know that when a promoter is unable to control the gate he is also unable to accurately gauge event attendance. Is the woman collecting shells on that little strip of beach on the Outer Mole in Key West really a spectator? Methinks not, but you can bet your butt the promoter will count her as one.
So offshore racing is a tough sell for sponsorships. Give guys like David Scott credit: He bought in AB for years. He'd also be one of the first people to tell you that August Busch III is a good friend of his, and that sure helped. And when In-Brand bought AB, that was that—done. (To be fair, they slashed all of their sports sponsorship and advertising budgets.)
Can offshore racing ever attract high-quality, big-dollar non-endemic sponsorships?
We'll never know until we give those sponsors a better product. It is so, so possible ... with unification and consolidation.
Off the soapbox.