How do you know AS didn't raise their fares first and WN matched? Either way, Alaska and Southwest always have the same fares on PDX/SEA-PHX. Their sale and walkup fares will always be mirrored.

In the last year, I've paid $75 to $400 o/w for PDX/SEA-PHX on both AS and WN. I've never seen $89 fares here on a regular basis (only during sale times). You might want to take a peek at TUS, but to be quite honest, $150 is a good fare to Arizona. Or just wait to come here in July.