It’s because Alaska seems to have caught on to this plan, drawing a line around the Pacific Northwest and declaring a heartland of its own. (Yes, yes, this is where you question the wisdom of that acquisition… again.) Alaska largely stays away from Southwest markets when it can — San Diego is an exception. None of those are currently Southwest markets — except for Boise which when served by Southwest is seasonal and less than daily — and they all should have decent fares. This helps make Alaska more relevant in Burbank, but more importantly, it further solidifies Alaska’s dominance in the PNW, its heartland.