Open class has been the foundation of beach-cat racing since it started almost 50 years ago, and it is STILL the foundation. If the past is any predictor of the future, open class will always be the foundation.
Along the way one-design classes (and formula classes) spring up. Some survive and some die. But I think open class racing will always survive.
We would not have a fleet in Miami now if we had not formed an open club that welcomes all classes of cats.