They keep saying things like "arid, parched" which leads me to believe they are looking at land in West Texas (it is very cheap land). These things do not apply to South East Texas, which is mostly subtropical. However, even in the South East we've had issues with subsidence due to over pumping (which we've mostly weaned off from), so the point of being self sustaining on surface water still applies.

East Texas has a huge logging and tree farming industry, so if you're building in East Texas, you'll probably want to leverage the natural resources; rammed earth doesn't quite make sense there.

Also, and this is my personal opinion, I do not believe it is possible to create a successful, large town without vehicles or air conditioning here, it isn't practical, and it isn't in the culture. If you look at the history of success of Texas towns, many further West and South/South East did not become successful until the advent of the vehicle and the air conditioner. The idea of lugging groceries for even a 150m walk in this weather sounds miserable. I recommend the author looks more local to find out what makes Texas towns tick rather than global, because while there's great ideas from around the world that could be imported, you shouldn't discount the local maxima.