Sorry to redirect this thread back to the park aspect...
I will bite and daydream with you.
Indoor park, no.
Outdoor, yea. You could save millions of imaginary dollars by eliminating the indoor aspect.
so lets say money was not an object to be considered for the initial construction of a facility and you only had to get it to pay for itself to keep it alive.
Since I live in south florida, there are not a bunch of places to ride flatwater, nor is it common to get a nice swell to ride surf. The idea of a complex that had lakes, wave pools, etc. could potentially have appeal. Every day I drive past huge man made lakes from mining lime rock. These huge holes are just there doing nothing but holding water. Here is an aerial photo of one such mining operation.
IF there was a way to gain access to these lakes to convert them to some mega complex of wave pools, wakeboarding/ski boat access, etc. the hard part of digging a giant hole is already done. The challenge then is to develop/install a wave machine, of which there are various systems already in place throughout the world i.e. WSL surf ranch. You would have to appeal to surfers, jet skiers, free riders, boat users, etc. just to break even and keep the doors open.
Again, being that this is south florida, winter is like 90 minutes long so you could be open year round. The indoor facility would never, NEVER work. To put your ventilation cost into perspective, a local "Cutting edge" gun range spent over two million dollars on their ventilation system and their entire facility is about 10,000 sq/ft.