I would guess that their ticket allotment was minuscule at best. Consider both Universities, Corporate posers, the News and Media plus Atlanta officials. They would have been lucky to get 500 to sell.
Are you sure it's sold out? Could they maybe wait to sell more/ most of the tickets till the teams are both actually announced?
Ticketmaster couldn't have had many tickets available. I looked at their website very soon after it became known that Auburn was headed to the Outback. The only tickets that came up were in the corner of the end zone, upper deck. Worst seats in the house.