How long is it going to take St Kilda, playing 2 games a year, to pay back to the cost?Obviously, you wouldn't play games likely to draw a big crowd at a smaller stadium. The very reason to redevelop the smaller grounds is to save clubs like St Kilda and the Bulldogs money and to limit the likelihood of playing in front of 12,000 people in a 50,000 seat stadium. Saints fans would love Moorabbin to be redeveloped into a 20-25k seater where we would still get a reasonable crowd Vs GWS or Freo and not lose precious money we can't afford to lose, and it would certainly help to have it for our eventual AFLW and VFL sides.
I can't honestly see any downside in it, the cost could easily be recouped and would pay for itself very quickly, and I highly doubt the AFL would ever charge $50 to go to a smaller stadium just because it's smaller.
It sounds like you don't want it to happen because the Bulldogs will then pull out of playing games in Ballarat, which comes off as a bit selfish.