In much of the west coast, and near western state, local housing prices are often driven up by Californians leaving the state with either lots of savings and/or equity cashed out from the house they just sold. So there has historically been a lot of anti-Californian backlash in places like Seattle and Portland, whose house markets haven't always been hot in their own right.

Imagine you live in a place where the average salary is $50k, but it's a nice place, and often people will move to your place from somewhere where the average salary was $200k. Economically, it is difficult to compete with those people for things that are already scarce (housing).