It became a niche segment in the real estate. The idea is you find land that is cheap, but you have a feeling it has mineral wealth. You buy it cheap, get the survey done, and show that it was really worth a lot more. But instead of building a mine/oil well, you declare the land undeveloped for perpetuity. The tax benefit you receive is commensurate to the (now highly increased) value of the land.
You make a profit this way, and the environment benefits.
It's a very risky part of real estate. There are lots of environmental groups who closely monitor the land, and will file a lawsuit if they suspect you are developing on the land. Fighting lawsuits is part of the risk.
Anyway, the person who did the presentation showed some interesting statistics. Supposedly, for every 10 acres of land that is developed in a given year, roughly 9 acres are declared undevelopable for perpetuity. That's really significant (if true).
In theory it's possible to reverse but in practice it requires something like standing on one foot, holding your breath, and reciting the entire bible.
People desperately need housing and even in bum fuck nowhere where I live they are desperate to build a little homestead just so they can have something, and then you have this insanity with people creating covenants that basically have dead people in their graves reaching out to smite living people.