I said I don't want to guess, and I wish I knew the answer.
It seems too simple just to say it's because of the yacht clubs, but that might just be it. I don't honestly know how Optis are promoted to kids. It seems that they are exposed to them early (older siblings, mom/dad at the club for something else, etc.) and they see 50+ boats with kids sailing them, maybe that's enough incentive???
Beyond Optis, there are other boats to take a kid through high school, college and beyond. There are established programs, and I am unaware of ANY college that races cats. So between what they are seeing at the clubs, what they have to grow into (mom/dad influece?), what their friends are doing, etc. where is the incentive to sail a cat (other than to go fast).
So again, the boat doesn't matter. The Opti is a very, very slow tank (OK, more of a box). But, put a whole bunch of them on a starting line, and somehow, they're fun!?!?
Although, back in the 80s, there were routinely 200+ boats at weekend Hobie regattas in the US. Granted, those were primarily for adults. Obviously, we let the genie out of the bottle, and then it ran away. We're clearly not doing a very good job of bringing in new sailors. Lots of people are trying, it's just not working like it did in the "heyday." The factory says they're selling more Hobie sailing boats than ever, but the models they are currently selling just aren't making into the existing regatta program.
As for 29er vs. Wave, I don't know if this was company-wide, or if the dealers will admit to it, but I know for a fact that they go out of their way to promote Waves as being used for casual-sailing (non-racing) only. They typically don't even tell these sailors about the local Hobie fleets, which they view as only being for the "serious racers."
The class association didn't help this in the beginning, as Waves were not accepted as a racing class for many years. While there are now class rules published by IHCA, in the US, the vast majority of Wave racing is done under a separate umbrella. Rick and Mary can fill you in on more of that (if you haven't seen it here already)...
