Not for profits can go broke. The risk, like with any bubble, is over commitment if their is a sudden economic shock.
It would be a tragedy if the AFL were damaged in this way.
I would suggest the AFL are much better placed to handle any exogenous financial "shock" than their competitors.
The A-League would pretty much go broke, so would the NBL for that matter - they already struggle to keep 8 teams going.
The AFL is in the strongest position given the depth of membership backing up the competition.
In a competitive sense, an economic or financial "shock" could well benefit the AFL competition as a whole medium-long term.
Plus - where else are professional AFL players going to go to ply their trade besides the AFL?
This makes it easier for the AFL to cut salary caps in an emergency without any player exodus unlike sporting competitors like the NRL, A-League, NBL etc, even Big Bash for that matter!