I had a good trip to some NF land in N. Georgia last fall and found quite a few opportunities for dispersed camping. I have also noticed that in some areas of North and South Carolina mountains many of the FS side roads are gated and locked leaving not much opportunity to explore and dispersed camping. It feels like they really try to limit access as much as possible. I'm not an outlaw but I sometimes feel like cutting some locks! The more popular areas seem to limit access the most. I know other areas that are very rural and only hunters go there and with a little exploring there are plenty of little secluded spots. They are just in the middle of nowhere. Go up into the Smokies and around the Blue Ridge Pkway and the side road gates will be closed more often than not. There are some dispersed sites up there but very few that I have found. I have found some hidden gems and it takes some exploring because they will not usually show up on any maps. "Beat the bushes" takes on a real meaning when looking for dispersed sites. A "universal key" might also. I'm about so old I don't much give a rat's ass if I get cited for using public land that's locked away for no apparent reason.
This is definitely the trend and its having the opposite effects of conservation! Instead of people being spread out and limiting the number of travelers on any one forest road now practically everyone is on the same couple trails in a given area so when it gets eroded after heavy traffic and rainfall or gets trashed, everyone gets blamed. Plus when theres only three trails in an area, everyone ends up knowing about putting them up on facebook, youtube, etc... Idk overlanding is kind of in a conundrum, the more popular it gets the more it will kind of kill itself. Either by making previous secluded and isolated places busy and taking away that aspect or by trails and dispersed campsites getting shut down. Unless some of this attitude towards overlanding/offroading--but I think more importantly towards cars in general--changes the popularity of the hobby doesn't help sadly. You would think that if parks and forests for us to BOTH conserve and enjoy and there was a rise in such a hobby that they would actually figure out ways to expand opportunities for it, not limit them.
I'm sure the excuse would be "environmental impact" which for too many people boils down to "cars are gross and I dont like them". There are lots of things that have an "impact" we minimize the impact (to an extant) and spend resources to make up for the impact (think of hunting). This is getting offtrack now (no pun intended) but I wouldnt even be opposed to seeing 4x4 permits like OBX has for driving on the beach. You pay a pretty small amount ($50-$125) to drive on the beach, before getting the permit you have agree to the rules, and the permit lists some of the rules and the things you are supposed to have on hand. Having a similar national forest 4x4 permit where agree to stay on the trail, have a trash bag with you, etc, etc could help by 1: educating and reminding people and 2: pay for trail repairs and clean ups. Personally I dont even think any of that is necessary and could really just work by spending the money we have now more efficiently. And we all gripe about the trash and stuff that people leave but honestly like every trail around here is adopting by some club and gets cleaned at least once or twice a year not to mention there is a lot of people who do go to a great deal of effort to clean up after others. Personally I think the impact of 4wd and overlanding is minimal and unproven by studies. While its popularity is exploding its still a tiny fraction of people that do it and the land percentage use of an 8-10ft wide trail is very small. And the impact could be even less by NOT maintaining some of the trails through leveling or graveling (both of which increase the traffic on a trail), I personally, and I imagine many here, would love to see more UNmaintained trails (in regards to the surface, not trash or brush obviously).