I suppose anything can happen eventually. There was a very long time period when it looked like the GOP would be locked out the South forever. And that changed. I don't see much progress in Texas. The Whites there are so Republican and the Hispanics don't vote much and aren't all that Democratic either. Consider Harris County. It's barely> 30% white, contains the biggest city in the state, and, of course, excludes the enormously Republican suburbs of MontCo, but was still only a tie in the 2012 election. That's what's the Dems are up against in Texas.
Yea, Texas is a rare case where Whites are more partisan in their voting behavior than the main minority group. Texas whites vote around 75-80 % Republican and Hispanics in Texas are less Democratic then the national average. They only vote around 60-65% Democratic. Democrats are going to have to wait until whites are like 25 % of the population to win which will take a long time.