We're not talking about only 3 clubs. We're now talking about Port Adelaide & Sydney as well in the real world. There are very few clubs that are bulletproof.
Remove the three struggling melbourne clubs and the AFL would continue to thrive as a national competition.
Remove Sydney, Port, and lets say the next struggling non-Vic club in Brisbane - and the league goes back 20 years to a VFL like existance - and without anywhere near the same level of corporate support and TV audience appeal.