there has been a huge demographic shift in Texas it's not really debatable if the demographics are changing. non Hispanic whites were around 65 to 70 percent 50 years ago to about 37% now. Hispanic went from around 12% to around 40%
Yes (although only -13% white / +7% hispanic over the last 20 years isn't that big of a shift), but the demographic shift could also be explained by legal immigration (especially from Mexico), where Texas is one of the top destinations (alongside Florida and California).