I think you only need to look at the yachting market to realise what could be done in GA. Its the same kind of people who sail as who fly. The average boat costs as much as or more than a plane. Marina fees are usually more than hangarage. The big marina operators have come in in the last 20 years or so, run the marinas like proper businesses and invested; and people are willing to pay for the product these guys provide.
Sunsail is one of the biggest sailing holiday providers - they provide new boats, good locations, good staff and they are successful as a result. And best of all, the punters buy the boats for them. GA schools could do this.