I don’t think that’s true of RV culture at all. I currently live on the road with my partner, and while we don’t yet have kids, we’ve met dozens of families and many more dozens of kids. All were more than capable of socializing and making friends, both with adults and other kids, and could often be found running around whatever campground or forest we were parked at. Certainly you can live a very isolated life on the road, but just like when living in a house if you put yourself out there there is a welcoming community that will respond.