I get the current Airline business model, the cheapest tickets are the ones purchased far in advance (usually). This benefits the airline, they can determine in advance how much fuel they need, they can cancel the flight if there isn’t enough passengers, how many meals they’ll need, etc.
However, once that plane pushes from the gate those unused seats are now worthless. If you want to purchase a ticket at the last minute prepare to pay a high price. Wouldn’t it benefit the airline to come up with some way to sell unused seats just prior to takeoff at a low price to encourage people to fill up those seats?
Yeah, it might cause people to always wait until the last second, but there would be no guarantee of an available seat. I just find it strange that you have a perishable product that gets more expensive the closer it gets to being no more.