No Stupid Questions

Basically, that's not where the farmland is (or, when it was first being settled, the fur, which provided the major economic incentives for why that area was settled in the first place). You also have to think about how the land was settled. Settlers from the east used mountain valleys to get around. Mountain valleys in that circled area aren't easily traversable and don't go anywhere or lead anywhere useful. Settlers from the southwest used ships and followed shipping routes up the coast. When you consider both these settlement methods simultaneously (and they were in fact used almost simultaneously) you will come to the conclusion that these are some of the most remote areas to be settled in the continental US, and their relative remoteness has a lot to do with why they were settled the way they were.

Meanwhile, from the perspective of a ship sailing up the coast there are few good protected anchorages to use as a sheltered waystation or safe harbor in case of inclement weather directly along the coast, but if you go just a little further you'll reach good port lands (it's literally called "Portland") or Seattle and you might as well journey just a little further to stop there instead if you possibly can. When you consider people taking a long and perilous journey around the horn of South America (there was no Panama Canal) you're almost at the end of the line, and you aren't going to want to stop 99% of the way, you're so close that you'll push on to the end, and that's why Portland, Seattle and Vancouver developed where they did. The farmland got worse the further north you went and became increasingly unsustainable so nobody really went much further before the gold rush provided yet another economic incentive to draw people there, but that's a different story.