National Parks are just one type of designation. There's 20-plus different designations, and that's just at the federal level. Wikipedia says 13% of the land in the US is protected (which is about 10% of all protected land in the world), but I believe certain designations allow for some level of exploitation (hunting, mining etc).

https://en.wikipedia.org/wiki/Protected_areas_of_the_United_...

Yeah, just looking at National Parks grossly undercounts and, if anything, National Parks are generally more developed (though have more protections) than a lot of other federal properties. Of course, it's somewhat uneven in terms of location. Federal land is disproportionately out west and in Alaska in terms of acreage.

Also logging and ranching, combined with the lack of large predators like wolves, bears and wild cats has had a pretty large impact

We also have some national security zones that are off limits to development.

Nevada National Security Site, for example.

National parks with roads running through them.