It would be more likely than a league would. I am sure $1 million plus per club (roughly a third of which is likely to be sucked up by travel and accommodation) could be used to greater benefit for football than a second-tier league. The AFL won't throw $12 million down to fund 12 second-tier teams.
The only issue is finding a sugar daddy to sponsor it and cover costs. As we saw with the Foxtel Cup, second-tier football isn't going to fill the grandstands and be a money-making venture. They would need a sponsor that understands this.
An AFL reserves competition is much more likely with the result being a plundering of the stocks of second-tier football, rendering the concept of a second division dead in the water.
One of the reasons why the Foxtel Cup failed is because the clubs that participated in that comp still played in their respective state leagues.
A national second division (NSD) should be a league where the clubs play in permanently, so their spots in the state leagues would be replaced or have their reserves team play in.
NSD allows the strongest state league clubs to play in a challenging comp that would enable the club to reach its full potential.
This is the league where you would place your West Perths, Norwoods, Williamstown, etc. And it would also be a great league to test AFL expansion teams such as the Tassie Devils or Canberra Griffins for a few years before entry into the Premiership league.