Again these are just a bunch of assumptions built into a castle of cards, by your logic prices would always be too high anyway. You know what you also missed? that prices could be even lower if passengers would agree to fly stacked in chicken cages or standing, so how come they fly anyway?Sigh. I always have to explain this. Because it's a business, and a business caters to its customers. Only a small percentage are willing to pay extra for first class, hence only a small percentage of seats are larger. Most people want to pay less to get where they are going, so in order to make a profit the airlines have to squeeze a lot of low cost seats together.
Lots of coach class tickets = low prices = lost potential income = could have made more and maybe bankruptcy
Pricing would be more equitable/flexible, if you were actually renting floor space for the trip, plane manufacturers just have to be inventive in coming up with a system that allows that.