On top of the large costs and permitting issues, you also have to build the business and that takes time and money. Unless the park is part of KOA there is no nationwide reservation system like hotels have. Since RV parks have a wide range of quality, many people rely on reviews to make their choices and a newly built park will not have any. It will likely take years before a park has enough exposure to be known to most RVers.
Finally, another variable has now entered into the equation. Any potential investor has to worry about whether or not the next round of viruses will close them down for months at a time. I believe if building a park was a highway to huge profits it would be a well traveled road, which it obviously isn't.
