The Californians, after years of having higher salary, more savings, and a job that lets them move, goes to Texas and offers $400k for that same house. The Californian thinks it's a great deal, because they get the same size house they previously lived in for only half the price! And the seller thinks it's great, because he now suddenly gets a huge premium on his previously-valued-at-$250k-house. All of the real estate responds in kind, expecting to get $400k+ from all the Cali transplants. However, the average Texan, who doesn't have that high paying salary, gets priced out and can no longer afford a house in their city.
This has been happening en masse to the northern suburbs of Dallas, as well as many neighborhoods in Austin. It's gentrification, more or less, and it comes with all the same problems.