Also various laws and regulations: van life is incompatible with many cities and is incompatible with schooling for children, possibly even child welfare laws. Zoning restrictions mean tiny houses can’t be built in many places.

Much of that is not unreasonable — e.g. I went to a high school which had a lot of children of migrant farm workers who were definitely held back by their parents’ need to migrate up and down California following the harvest. Stability has merit.

What I would focus on are the zoning laws forcing single-family houses, lawns, vast amounts of parking, etc. since those increase the cost of housing significantly and reduce supply. There are many owners who would consider subdividing housing, tiny houses/granny flats/basement apartments/etc. but can’t because that is banned outright or requires things like street access and subsidized parking which aren’t compatible with the available space.

Unfortunately, in the United States this also inevitably involves class and racism — the laws against density, people camping or living in vehicles, etc. usually trace back to fears of poor, often brown, people living outside of “their” neighborhoods and especially outnumbering the current residents. That sentiment is long-lived and hard to shake, no matter the professed politics of a community.