That Kardina Park final was meant to be at Etihad due to MCG hosting 3 finals that weekend (Haw v Syd - Rich v Carl - Coll v Port). If you remember Demetriou was having a spat with Etihad at the time so shafted them the opportunity of hosting it and moved it down the freeway.Makes sense.
Small flaw in your logic, if I may.
2012 final. Geelong v Freo at the MCG. Attendance 44,460
2013 final. Geelong v Freo at Kardinia. Attendance 32,815
On past finals figures, wouldn't the AFL have made more money playing the 2013 final at the MCG given they would have had a higher attendance?