I don't remember the exact quote or which Delta executive said it. Around that time, they asked themselves, "What single thing does a business traveler want most out of an airline?" Their surveys' were clear: They overwelmingly wanted the airline to run on-time. Delta decided *that* would be the immediate focus. (The later decided to cut ff benefits to increase profits, but that's another story.)

There is a cost to improve on-time performance, but there is also a cost to run consistently late flights. (I'm not even considering the lost customer goodwill, which has to be an additional factor.)

On UA versus DL hubs, I think their respectively reliability pairs up pretty well:

EWR versus JFK: JFK has severe ATC delays
IAH versus ATL: ATL has frequent thunderstorms
ORD versus MSP/DTW: Both have lousy weather, but ATC worse at ORD
SFO versus SEA/SLC: UA probably has a reliability handicap on the west coast, but overall I think Delta's hubs are about the same in reliability.

Airlines don't have to be the same in order to be financially successful. Spirit and Delta have radically different customer-experience strategies, yet both seem to be working. United should be asking "Is there a market for flyers who want prices a bit lower than what Delta charges, but with a comfort and reliability experience somewhat akin to what Spirit offers?"