Texas is a solidly Republican state for one reason; the GOP routinely wins over 70% of the white vote. That’s it. What happens when the white share of the electorate is no longer large enough for that to carry the day?
The GOP may do better with Hispanics in Texas than they do in California, but they still typically lose the latino vote by large, double-digit margins in the Lone Star State. And there is no reason to expect this to change, especially while mass immigration (legal and illegal) continues.
Texas won’t become hopeless for the GOP like California as long as the white vote there remains so conservative, but Texas will likely become a battleground state within a few election cycles.
Ok, so we are doomed. But I can still wash the bad news down with a Shiner. So, it's not all bad.