So, PDT would rather have an FAA Part 135 carrier flying Cessnas out of a different terminal in PDX than someone who would codeshare with NW, DL, and AA, and also has connections to a lot of the Pacific Northwest?

Ooooookay... that sounds pretty wacky to me, but maybe the folks in PDT think a bunch of Cessnas are more likely to work financially for the carrier than a Q400 would over the long term (especially if the EAS support goes buh-bye).