it's hardly something for NOTHING-- it's something for directing your $5000, $10,000, or $15,000 worth of flying [spending averages for the various elite levels] to one particular company instead of its competition. that's a car. and no car dealer could treat any customer as some airlines do and get away with it.

one can quibble over the levels of benefits, sure-- the market price of these "rebates" is bound to fluctuate. but deliberately annoying people who control meaningful blocks of your revenue is suicide.
at the margin, replacing even a single Gold level customer totally would require finding up to 50 single-trip grandmas to pay $200 each for one trip.
only it would be more than that, because the Gold member's place would be taken on each flight only by someone willing to pay a little less for that seat.