You are oversimplifying the writer's position. They mention zoning as one reason but also other regulations, health codes (minimum sink counts!) and other thin

You are oversimplifying the writer's position. They mention zoning as one reason but also other regulations, health codes (minimum sink counts!) and other things like parking minimums (which houston has had, though they've been removed recently in a lot of cases), reliable and ubiquitous public transit, etc.