There is no doubt Moorabbin has got a lot busier of late. The seemingly ever increasing fleet of Soar Aviation's yellow Foxbats along with the large fleet of Oxford C172's with their foreign students, all competing for airspace with RVAC, MFT, MFS, MAS, Bini's etc etc means the place is very busy most of the time. Why have the training numbers increased..? Well from what I've been told (this is a rumour network) Soar are cheaper RAAus and don't have to pay landing fees (can someone confirm this?). Oxford are obviously training a lot of overseas students.
Maybe Glen B can offer some more insight into what's happening there..?
As far as Bankstown goes, given the uncertainty about it's future viability I'm not surprised the place is struggling.