Just like you wouldn't want to use MLS stadiums when judging the US, I think the same would be true for Australia and the A-League. I'm sure a sport-crazy country like that has plenty of stadiums that are big enough.
Looking at the link Andy just posted, I don't think that's the case. There's a cricket ground that seats 100,000, and the only other stadiums that seat 80,000+ are a horsetrack and an F1 racing track. The other largest stadiums are the A-League stadiums.
huh?ANZ in Sydney seats 83,000 and was built in 1999.
Melbourne also has
this place, which is brand new but smaller.
They have 2 cities that have hosted the Olympics. I'm sure they could host the WC. Are 80,000+ seat venues a requirement? How many does Qatar have, or Russia, or just about anywhere but the US?
80,000 was an arbitrary figure, and I think my point was lost.US Stadiums during the 1994 World Cup (capacity):
Rose Bowl (91,794)
Stanford Stadium (80,906)
Pontiac Silverdome (77,557)
Giants Stadium (75,338)
Cotton Bowl (63,998)
Soldier Field (63,117)
Citrus Bowl (61,219)
Foxborough (53,644)
RFK (53,142)
In contrast, per the link that Andy provided, these are 9 largest stadiums - of any kind - in Australia at the moment (note that I have left out the 130,000 Flemington Horse Racing Ground and the 80,000 Albert Park F1 Track, as they're not really soccer stadiums):
Melbourne Cricket Ground (100,000) - cricket and Aussie Rules Football
ANZ Stadium (83,500)
Etihad Stadium (56,347)
Suncorp Stadium (52,500)
AAMI Stadium (51,515) - Aussie Rules Football
Queensland Centre (48,400) - listed as a general-purpose venue
Sydney Football Stadium (45,500)
Princes Park (35,000) - listed as a general-purpose venue
Adelaide Oval (33,597) - cricket
My point was merely that if FIFA had to make a short-term decision (say, for example, FIFA determines that Brazil isn't capable of hosting with less than 2 years to prepare), the USA already has the stadiums in place that are sure to sell-out in record numbers. Maybe Australia could build them - I don't know about Australia's economy and I won't pretend to. Maybe stadium size and ticket sales play no real role in FIFA's decision-making, anyway.