Houston has zoning though in the form of very high parking requirements, and it's exactly why there are sprawling strip malls for miles. A better example of what a city without zoning would look like is New York (since most of the buildings were built before modern zoning locked what was there historically in place), but especially the tenement districts of the lower east side.

Manhattan has churches next to skyscrapers next to liquor stores, and nobody seems too bothered

Because you don't need a car to get to most places. Houston is the antithesis of NYC in terms of urban planning.

And that works better than you might expect. You'll probably need a car, but the places you need to regularly go are nearby so you don't spend a lot of time in traffic, and housing is cheap enough so that you'll likely be able to live close to work.