With Southwest's new fares announced May 18, they have priced themselves above American and Delta while lowering many markets to almost no flights.
Here is the example. I fly to ECP (Panama City Beaches) monthly and now the fare is $801 round trip with most flights having two stops no where near a straight line (ie Chicago, St. Louis). Delta is $655 through Atlanta. I can lower the Southwest cost by booking all one way's through Houston or Nashville to $755. It used to be under $500 with one stop each way.