Uassigned seating with one cabin class has worked. And worked well for almost fifty years. Their finances speak for itself. It was the most profitable airline in history with better margins than all the lagacies. And that is with no premium seating. You don't buy back six billion in stock without sufficient free cash flow and good margins. Post COVID world has forced their hands. Customers flying habits and tastes have changed. They are willing to upcharge what ever the airline offers. Can't squeeze any more money out of the product. As somebody else has pointed out, this is a revenue problem. Nothing will change with turn times IF they go to assign seating. I think the easy thing to do would be just to give up the open cabin and do assign seating. No costs required for that. The harder part(they already admitted this on the CC) is will SWA customers want to upcharge for something else. Stay tuned till Sept investors day for that.
I would highly recommend listening to the pod cast the SRC put out. 4500 flights day this summer. Shoulder flying coming back, with reduced flying days on Tues, Wed and Sat. Thats not a good recipe for the high dense trips that the summer usually brings. Wait for the red-eyes. Can't wait till they try to reinvent the wheel on that.