One of the problems is that business travelers need to be swayed more. The lack of lounges, international routes, any catering on long flights (over 4 hours), cramped chairs regardless of loyalty / status, etc., has hurt them, while the competition has caught up with no change fees. The comparable pricing between WN and others doesn't help either.
I took WN to Hawaii, Cancun, etc., and the lack of real amenities / food on those longer flights were painful. I'd rather pay more for premium economy on longer flights to have a more relaxing, less hungry experience.
Hopefully things are turning around and WN will become more competitive with amenities and better loyalty rewards.