If this was the case, the AFL would have done it by now already. I agree with the theory - I just don't think the AFL's research (which we know they do conduct) will show this to be the case in practice, at the moment.Every odd Melbourne based supporter loss will be more than cancelled by the gains. Once again it is done around the world, we know all this.
A lower supported team is actually the ideal. If you lose 10 per cent of North supporters initially it is only x amount. If you lose 10 percent of Collingwood supporters initially, it is far more dramatic. Nonetheless however, the long term completely outweighs the short term losses.
The moment they are confident it will be the case, they'll move a club in a heartbeat. They'll turn the screws by tweaking the 'equalisation fund' distribution so that these meek 'profits' are profits no more. They'll give the club awful fixtures so crowd numbers dwindle further. They'll turn their 'accredited media' on them to ensure public perception is that the best option is to move.
The AFL get what they want. When they have time to execute it, they always have and always will. It's their game. They're just letting the clubs take part in it.