The "I can do anything I want when it comes to a vacation" crowd is now very much limited to RVing. These are the people that have boats, RVs, the funds to take overseas vacations and often second homes. If they happen to live in areas with severe restrictions the use of the boat may be forbidden. The second home might be in an area where the restrictions are severe, outbreaks are occurring or unrest is prevalent, so that is off the table this year. Finally, recreational travel outside of the US is almost completely impossible. You can't even go to Hawaii unless your plans include isolating for 14 days before actually vacationing. That leaves travel by vehicle and RVs the safest, most flexible in that regard. Add in the fact that many parks are either closed or have occupancy restrictions and you find the remaining parks are getting a bigger slice of the traveling pie. Even if that total RV pie is smaller due to COVID fears and shut downs, the piece available for the parks that are open might be bigger than the slice they got when things were the "old normal".
And don't forget, it is also a regional thing. Most people who need to plan long trips cancelled them due to uncertainty. It was not known up to the time they open when National Parks will open. Travel to follow your favorite Baseball team, or NASCAR driver is off for the year. Nobody is going to take their RV across the country to go to a cancelled music festival. That leaves near local trips, so parks near major population centers are getting much more business than normal. Areas dependent on those planned trips are suffering.
