Liberals are not a problem.
Those two things don’t go together.
Those cities have long been blue. The dems have the same “concentration” problem there they do on the coasts, just on a smaller scale.
It also assumes they stay stupid after they move, which is not always the case. In fact it rarely is. Oh there’ll be isolated cases of collective insanity, such as Austin trying to defund police, but cases.
Your sophomoric author is correct about one thing - it will be good for the GOP. The republicans are locked into the old paradigm - it is time to adapt or die.
The biggest thing he ignores is the radicalization of the democrats. Most people do not want that insanity in their lives. As long as the coastal enclaves left keeps escalating, the alternative will be fine.
There is an awakening among the Woke Adjacent™. It is slow but sure.