I mean maybe it's more about being able to take vacation time off to camp? At least, the more you camp, the more likely it is that you are well off. Plus you might need a decent car to drive out somewhere. A tent, sleeping bags, boots, etc. and probably some experience already doing that. Of course, you definitely can do that without being a labor aristocrat or something, but it's just one of those things that skews maybe. Definitely also depends on if it's car camping vs backpacking vs taking months off work to do some epic hiking journey.