There is a small market for winter camping but it's mostly short term mobile work that they are following. People going for pleasure in the winter are (and always have been) a tiny slice of the market. It's certainly not dry camping in the winter.
I would agree with the divergence of people either going big or going small with less in the middle.
- Snowbirds full timing but not neccessarily covering a lot of miles drive the market for big units.
- Younger folks looking at gas prices drive the small unit market.
I have a hard time predicting where the campground market will go. I'm sure you will see more 55+ parks in the south but that's less likely in the north where old folks aren't as concentrated.
I don't see state parks going away or seeing a huge upgrade in services. They are just too popular in most areas. Why would they dump huge amounts of money into a park that has little oppurtunity to get higher occupancy.