It's even crazier to think about that Houston isn't an example of zoning reform – they've never had any zoning to begin with! You can essentially build anything you want, anywhere, of any density. Yes, even skyscrapers in a residential area [1] or an industrial crematorium in the middle of a neighborhood [2] or, most famously, an amusement park-house-hybrid [3].
The problem is just that Texas, as a whole, has a planning philosophy of outwards, not upwards. Things are densifying in job rich areas now that they've just about expanded as far as they can (the city proper 669 square miles, or about twice the 5 boroughs of NYC, twice the geographic size of its sibling city Dallas, and 150+ square miles larger than Los Angeles; none of these sizes include surrounding suburbs, by the way).
All of this is long way to say that you're right – it's not just about zoning. It's equally about ending the grip of car-centric planning and not just allowing, but incentivizing densification and walkability. The fact 2/3rds of Houston is in (increasingly-frequent, due in part to the sprawl itself not allowing anywhere for water to runoff to) flood zones, too, is apparently not incentive enough.
The problem is just that Texas, as a whole, has a planning philosophy of outwards, not upwards. Things are densifying in job rich areas now that they've just about expanded as far as they can (the city proper 669 square miles, or about twice the 5 boroughs of NYC, twice the geographic size of its sibling city Dallas, and 150+ square miles larger than Los Angeles; none of these sizes include surrounding suburbs, by the way).
All of this is long way to say that you're right – it's not just about zoning. It's equally about ending the grip of car-centric planning and not just allowing, but incentivizing densification and walkability. The fact 2/3rds of Houston is in (increasingly-frequent, due in part to the sprawl itself not allowing anywhere for water to runoff to) flood zones, too, is apparently not incentive enough.
[1] https://s.hdnux.com/photos/51/06/32/10774164/4/1200x0.jpg [2] https://s.hdnux.com/photos/51/07/70/10780179/4/1200x0.jpg [3] https://s.hdnux.com/photos/51/07/64/10779939/4/rawImage.jpg