Trust me radishes, most of the people moving to Texas are not moving there for the quality of life (unless they are coming from Mexico, where it is a step up in many instances), and definately not for the running opportunities. People (and more importantly employers) are locating there because of the low cost of living, some decent schools and an affordable work force.
One other thing all of these cities have in common (with the exception of Austin) which you neglect to mention is that they consistantly rank in the top ten for most obese cities in the US. Maybe you know something I don't, but when I lived there, I found it to have some of the worst access to open space (again with the exception of Austin), some of the least runner and bike friendly roads (in most places there was no shoulder), and one of the least healthy populations I have ever witnessed (type 2 diabetes and obesity were rampant).
Just because a city is growing doesn't mean it is a nice place to live (unless you enjoy sitting inside watching television and eating fried food and barbeque).