Damit dude, quit giving SouthWest Arlines any ideas!
But seriously, you are making a contract between yourself and the airline to fly to a specific destination. You are NOT buying a seat.
I have to disagree with your reasoning.
With most airlines (Southwest being an exception) you are assigned a seat, and at times required to be seated in it. You aren't buying it in the sense that you can use it whenever you so choose, but you most certainly are renting or leasing that space for the duration of the trip.