If Texas goes full California, the electoral collage is lost.
Texas’s electoral votes usually went to Democrats until 1980, and California’s usually went Republican until 1992. Election maps change, as they have throughout American history.
Republicans will probably not continue to win Texas forever. When that time comes, we had better be winning elsewhere. The Democrats will keep trying to win Texas until they succeed. They know they probably won’t win this year or next year, but it’s a long-term project for them and the Democrats who matter have patience.
By the same token, Republicans should be trying to win California and New York in the long run. There’s no reason we can’t. Our people are better, and our ideas are better.