I think it's becuase a big part of the Texas boom is natural resources based. Look at places like ND, WY, etc. That have had economic booms based on ntl resources, which are different from the service based booms in AZ and GA. TX is kinda a hybrid of the two I'd argue.
It's weird to consider this now but it is actually true that the Texas Republicans used to be reasonably good at investing in higher education and drawing high-capital businesses (through friendly tax structures, light hand regulations, etc)
