Don't give Southwest your business if you don't like their business model. At least in the USA you generally have a choice of carriers between most city pairs. To be fair, if you had rebooked at short notice on a pretty full flight with a carrier providing seat assignment, you probably would have ended up with a middle seat anyway. With some airlines you can select your seat when you make your booking and this can be months ahead. If you don't do this and check-in on line (even 24 hrs ahead) you may find that there's not much choice left either.