It seems one of Portland's standing economic 'problems' is that it is apparently very nice out there.

Which is to say: wages do tend to be lower than you'd expect given the cost of living, due solely the number of skilled and educated workers who will accept comparatively lower wages, just so they can live in/around Portland.

As they say: Portland is where young people go to retire. And as long as that's true, I'd imagine Portland salaries will continue to lag 'expectations' and almost certainly trail the Valley.