To remove, for the airlines, the old grey market of resold "non-refundable" tickets that which the original purchaser can no longer utilize that existed before the ID requirement.
There is more profit in being able to sell an unoccupied seat twice (once for the unused non-refundable ticket, a second time when the original ticket does not show up at the gate) than in allowing tickets to be resold on the grey market.
Then the airlines should be doing the ID checks. But they don't bother, because the TSA basically does it for them.
Pretty sure the stated reason for the TSA checking IDs is to keep people on the no-fly list from flying. (Worth nothing that the no-fly list is not without its problems). It also allows trusted traveler programs to work.
Not disagreeing with you or the OP about anything, but then this just raises the question for me of why not use facial recognition to screen against a no fly database (negative screen) than to verify identity (positive screen)? Or restrict it to trusted traveler on an opt-in basis?
The TSA approach and security paradigm in general seems poorly thought out and misguided to me sometimes.
Why do they care, though, if their margins are going to remain at X% anyway, because of market forces? They're just adding extra steps to the whole thing so a random passenger can benefit from my lost ticket money, rather than someone I explicitly choose.
Because if a ticket is sold privately to another rather than going unused, the airline only gets paid once. If the airline can resell the seat, they get paid for it twice.
When I buy tickets, they are nonrefundable. If I don't use the ticket, I don't get my money back (or credits). You can buy tickets that are refundable, but they cost more.
non-refundable doesn't mean what you think it means. you get a voucher for the ticket price (minus a fee) you can use on a later date so they aren't really selling the seat twice.
There is more profit in being able to sell an unoccupied seat twice (once for the unused non-refundable ticket, a second time when the original ticket does not show up at the gate) than in allowing tickets to be resold on the grey market.