Without zoning our cities would be denser, more eco-friendly, cheaper to live in, more able to produce economies of agglomeration, and more immigrants would benefit from American prosperity [source].
Tyler Cowen tries to understand the role of zoning in promoting urban density and makes the above presumption. Except it isn’t always true. Houston, one of the largest cities in the U.S. has no zoning per se (has highly restrictive deed restrictions though) but yet is one of the sprawling cities in the nation. It has no downtown to be proud of and although high-rise condos are springing up inside the beltway, growth outside the ring far outstrips that trend. Also, as some commenters in the above-linked post mention, Houston is unique in the sense that high energy costs means the Houston economy is doing well which leads to more commute times.
On libertarian grounds, it helps to understand more about zoning and it isn’t necessarily one-size-fits-all strategy. As another commenter points out, zoning can vary from being simply designations for land use to micro-managing growth by monitoring every little change in structures. If lack of zoning results in a chaotic urbanscape like Houston, I rather prefer some form of zoning.