That article comes so close to defeating its own argument it's painful. If that land wasn't protected with zoning, it would have been built up long ago into a typical sprawling suburbia – the opposite of what they propose. So if it had been unprotected in the past, that would have been bad. And if it stays protected that's bad because it's underused.

It is only this short sliver of time that is today that this land should be developed into their dream city. That will somehow miraculously withstand the test of time.

No, it won't, that's just greed and narcissism – thinking that we're so special today that we deserve to have that land unprotected for us but doing that for either future or past generations is a mistake.

What regulation prevents that from being built?

[Edit] The Williamson Act? (https://en.wikipedia.org/wiki/Williamson_Act) "The Williamson Act of the US state of California (officially, the California Land Conservation Act of 1965) is a California law that provides relief of property tax to owners of farmland and open-space land in exchange for a ten-year agreement that the land will not be developed or otherwise converted to another use."

"The property is under the Williamson Act, meaning the land will not be developed or otherwise converted to another use for a number of years." (https://www.sacbee.com/news/state/california/article23239941...)