[kgermino]

Are you on one of the coasts?

In the Midwest I know a ton of business travelers (>1 trip/month) who default to Southwest. The weekly travelers tend to prefer the legacy carriers if they're available (so I'm sure there's something to your point even here) but IME Southwest rules the monthly/short notice flyers around me.

[jaxn]

Weekly travelers prefer legacy carriers because they get upgraded to fist class, have special phone numbers for customer service and rebooking, board first, etc.

[mastercheif]

I can anecdotally back this statement up via experience with frequent flyers based in Nashville.

[mitchell_h]

Home airport is STL, I normally fly to the coasts.