DSM has been a legacy airline stronghold for ever, I do Omaha 5-6 times/year (did it last week) and drive to DSM. I fly every week and don't fly NWA, United or American anymore. I use Southwest most every week and will continue to drive into Iowa vs. paying legacy fares. My roundtrip fare last week was $230 vs. $400+ to DSM. Frankly my company now demands Omaha vs. DSM
Maybe you can explain the term "legacy fare" as I've never heard that term before. Also, I fly a lot for business and even in these belt tightening times, the flights out of DSM still remain competative enough to not justify driving to another airport. Maybe in your case it is a specific destination that just doesnt' work well?