I'll say this as simply as possible: It's not about the boats.
If you don't believe me, the numbers don't lie. I've done some RC work this summer in the mono world (Newport, RI and Narragansett Bay), and am completely blown away by the Opti program (Club 420s numbers are also impressive).
There were 90 boats at a weekend regatta in June (not a championship).
There were over 450 boats entered at one regional championship regatta.
There were 128 at another regional regatta.
A new Opti costs about $3000, in the ballpark of a Hobie Wave. Neither of these boats is a "performance" class (for its respective number of hulls), but the Opti program crushes any youth cat program, period.
I'm not going to guess what the reasons are, but the numbers are tough to deny.