Bilbo
I think this varies regionally.
In Minnesota, the state-run campgrounds and the private campgrounds are raising rates while the facilities, overall, deteriorate. The state parks have budget problems and are trying to run the entire park based on campground revenue, in many cases. Private campgrounds are unable to expand and new private campgrounds are unable to be built economically because compliance costs for the water and sewer system have become untenable under the current regulations.
What little expansion has occurred has taken place at county and regional parks, with Bunker Hills regional park and Lebanon Hills regional park, on opposite ends of the Minneapolis area, being good examples. Each of these facilities has multiple campground loops, with some laid out for big class As and other large rigs, and some intended for the smaller rig. Compared to prevailing rates 10 years ago, however, rates are high -- typically around $25 a night, for either type of site.
I have seen a handful of municipal and local low-cost or free campgrounds, generally without hookups, that mostly cater to small rigs.
The state parks nearly all are set up with a good share of smaller non-electric sites intended for tent campers and people with smaller rigs.
So I guess, in Minnesota, the mix isn't really changing that much, except that what little new campground construction is taking place includes more full-hookup 50A sites for big rigs than used to be the case.
I see a lot of people out in tents and pop-ups.