Well, they get to do whatever they want with their land. No matter how crowded the roads and schools get.
It might not be a problem for me forever. Since they can charge huge amounts to sell or rent new condo and apartments, the over-55 manufactured home park that I live in might be sold to developers at any time.
The main protection is that many other developments have already popped up like mushrooms after a rain. SURELY there is some saturation point, like no one being willing to move into such an overcrowded town. but who knows, with The Borg?
That happened to the last park I lived in. Since you own your home but rent the land, the owners can always sell their park to developers and give you 12 months notice to tuck your home under your arm and move it to some other park. The only alternative was to pay around $7-12K to have your home crushed and trucked to a landfill. And if you had any asbestos in your house, the price went up like a rocket.
That is marginally possible except that it tends to destroy your plumbing, and also the rash of park closures means that there were far more old people looking for a place to move their homes (or places to live, at all), than there were parks with empty pads.
Many old folks had to move out of the county. My current park is a big one. If it closed all at once, there would be hundreds of people having to crush their homes, and some new ones are said to cost up to $100K (pure rumor, I don't really know - but very old ones on a nice rented space can easily cost $50-70K).
I got "lucky". I found a guy who was cruising around, offering to take people's homes for free since he had rigs to move them to where they could be housing for farm laborers. He didn't want my old place until he saw our big new washer-dryer set. That closed the deal!
