The Texas constitution is written in such a way to provide defense-in-depth against an income tax, or any tax that even looks like an income tax. I don’t even think you’re allowed to file a bill with lege council that lets you file a bill to pass an amendment to remove the wording that prevents income tax—that sort of thing. You’d for sure get sued, and there’s no way the reps would keep their jobs.
That so many people from California will move to Texas over the next 20 years that it will change the voting population’s habits and Texas will get a state income tax.