Originally Posted by mother-

MSP, converse fallacy in action-
While it is true that frequent fliers in and around the hubs tend to concentrate on flying Delta, that does not conversely mean that most of Delta's frequent fliers are in/around the Hubs.

Certainly O&D hubs work better than non O&D (hence MEM, CVG, etc. are disappearing). I've never heard of the big market in IND (or Tampa) but the rest of those 'focus cities' (you somehow left out NY and LA, btw) are east/west coast, and likely to feed into the transcons in question...