Location, income, family structure ...
We don’t go to National Parks, either: it’s a huge and expensive undertaking with ten children, so we make other choices, such as renting a house at the beach.
Only six kids, but we don’t go to national parks either. Too much money and work. Our state park system is a great fit for our family. As we seem to be the only family left who has tents instead of an RV we get privacy as well.