Another way of putting the question is: In a relatively near future a foiling 18 foot catamaran will definitely appear, do we want this boat to be part of the F18 family or not?
Personally, I think that at some point I will want to sail such a boat (when a reliable and affordable solution exist).
If the majority of F18 sailors think the same it makes sense to think of an upgrade path for F18 owners, if not, it is best to keep the F18 as is. Another 18 foot catamaran class will appear and that is perfectly OK too.

Philippe