It wouldn't sell out, because the Medallion club and corporates etc wont go, so you will have 35,000 people there yet have about another 30,000 who cant get a ticket
Empty but sold seats would still be a sellout.
The only club this year capable of selling out Etihad on their own is Richmond (and even they probably still wouldn't do it) Collingwood wouldn't sellout the public reserve. You overestimate the people that are prepared to go on free tickets at the MCG but wouldn't pay $80 if they had to.