There simply isn't a sport that is even remotely commercially successful that pro-slalom skiing can be modeled after that I can see. While being the most difficult sport I have ever participated in, it is a niche sport with massive access barriers. The access to good water, courses and proper set ups (boats, ZO, skis, gloves etc...) is simply too hard despite the efforts of some to increase the availability. Even with that access it then takes a decent free skier possibly years to ever achieve running a full pass.
Snow Skiing and Volleyball are two things tossed out as examples to follow, but that just doesn't work as comparable sports. I pick those two because they are two sports I also participate in. The snow skiing industry is massive with tens of millions of skier days available to the general public regardless of where you live be it in Colorado or Houston TX (the true family vacation that everyone can do all day and return somewhere new and exciting every year). Same with Volleyball, it takes a sand pit available in just about every town, a net and a ball, thus, millions of people play volleyball everyday.
Water skiing is just not the same. There may be vast numbers of water skiers out there on public wakes getting their swerve on, but that isn't slalom skiing in a course, let alone shortline skiing. I can't count the number of times on our lake where we have had good free-skiers come, see @Marco run a 35 off pass and go I can do that and then spend and hour failing to make it around 2 ball @15 off 28 MPH. Contrast that with a a $10 nastar course lets any intermediate snow skier experience completing a GS course and get a fictional medal or a mini park that lets an intermediate hit a two foot rail so they can identify with a snow-skiing event; thus, snow skiing events have sponsors. There is an access and connection issue that is so incredibly hard to overcome that it makes the idea of profitable and viable pro-tour slalom skiing so difficult. For reasons enumerated by others sponsors need to see a reward and benefit for their advertising and sponsorship dollars and due to the access issues and lack of connection between your average water skier who makes up the bulk of those spending their money on this sport and short-line slalom skiing, that reward or benefit is so minimal because it reaches so few.
How the heck do we ever overcome these issues is far beyond me, but the problem is real, but never truly acknowledged. It is why the big dog is successful, because as Horton puts it, it is dudes putting money in a pot to be split by the winners. You are taking home your fellow competitors money, much like poker.
I do like the idea of a pro-waterskiers association of some sort as organization is needed and AWSA isn't going to provide that type of organization for the best of the best. They are too busy limiting access to the sport through insane requirements to hold even class c tournaments.