Lets not forget that many miles in the past were lost thru expiration. No one needs the loyality of someone who flies every 7 years!! That person picks who is available and who has the best price to where they are going. Reputation also plays a role as many of these people fear flying.

You really need to speak to an accountant or pour over the 10k's to see if the liability of these tickets is accounted for. Remember they are mostly used for seats that would be empty anyway, so the cost to the airline is minimal. Certainly reasonable accounting standards would allow little attention to most peoples dormant accounts.

As for buybacks, nothing short of a flight or an upgrade has any material value, or is so diluted as to make the value much less that first thought

Is this really a topic for a paper??