Were you the one counting the crowd at our NAB game?
I would have guessed there were less than half the 6,000 you're suggesting.
NB: Casey council reports that there were 6,000 there.
Regardless, my point stands - the parking may have been fine with 6,000, but to be a viable ground for real footy you'll need to cater for many times that - far more than what could be catered with parking IMO. Double the cars would have been a nightmare, let alone 4-5 times more.