“Workshop” theories of art, which trace characteristics of art to external constraints, generally leave me cold. In most arts very little stands between conception and execution. You think it, and there it is. Architecture is the exception. (Also movies, but to an ever-lessening degree.) For most of human history engineering knowledge severely constrained what could be built. Before steel-beam construction anything taller than a couple hundred feet was basically impossible.
No longer, of course. Even Frank Lloyd Wright’s mile-high skyscraper was feasible in 1956, when he designed it, except for the elevators, and that problem has since been solved. Theoretically we can build just about whatever we want.
In the 20th century what constrains architecture is law. Zoning regulations are a relatively recent invention; only in 1926, with the disastrous Supreme Court decision of Euclid v. Ambler, was their constitutionality definitely settled. Every major city in America except Houston is now zoned. The stepped-back skyscraper of the early part of the century, of which the Empire State Building and the Chrysler Building are the classic examples, was largely a product of the 1916 New York zoning ordinance. The dreadful tract houses of the suburbs, too, are a legal matter; without the rigid regulations that segregate residential from commercial use the suburbs certainly would not have taken their current form.
The Mies-Corbu school would never have seen the light of day without government assistance. Corbusier had built nothing but a few houses for his boho friends and a vacation place for his mother when in 1927 Mies brought him in to help out Weissenhof Werkbund project, an exhibition of worker housing sponsored by the German Social Democratic government. It wasn’t until decades later that private parties began to pay serious cash for the stuff.
On the other side of the spectrum things are much the same. Christopher Alexander, ideologically as far from Mies and Corbu as you can go without sailing off the edge of the earth, has had his largest commissions from the government of Mexico, and a public university, the University of Oregon. It is true that for the most part only governments are in a position to give out such commissions. This is because governments have spent a good part of the century arrogating to themselves the privilege of regulating land use. Do the architects complain? On the contrary; they demand that it be done in the interest of their pet style.
Zoning laws themselves are not ex nihilo: they come from ideas, and it’s perfectly valid to discuss those ideas. But most builders work under tight legal constraints, and it is a mistake to treat their products as if they sprang more or less directly from their heads.
King George I remarked of the Old Pretender that “He and I are in perfect agreement. We both believe we should be King of England.” So with architects.