Oh
here we go again.
I think this has a lot more to do with PDX-HNL not being a terribly high yielding route for DL, and they believe those planes can make more money flying elsewhere, perhaps internationally.
AS wanted to dip their toes into the HI market, and the 738-ETOPS gave them a way to do that without having to take the plunge into a new aircraft type. Sure, they occasionally have to leave a few bags behind, or take a fuel stop in OAK; but if hadn't worked out, they could have easily redeployed those birds elsewhere in the system.
DL serves lot more O/D traffic from far flung locales and the 757/767 is probably the best tool for the job of flying to HI for most large hub/spoke carriers. Besides the now defunct TZ and AQ, this is what every other major airline does.
Suffice it to say, given AS's position in the market the 738 is the right plane for the job, but not necessarily for any other carrier.