I echo what most people in here are saying, it's Employers unwillingness to invest in Training. I understand that training people and investing in their training costs money and involves risks, but there are ways of mitigating that, get people to sign a contract that says they agree that if they leave within a year or 2 they are required to pay back training costs at a pro rata rate! That way no one is forced to pay upfront, it keeps people in the job for a couple of years and covers the Employer as well.
Also paying Pilots properly would be excellent, the training is so damned expensive yet the EBA for a SE Pilot of a normal C206 or Airvan for example is just shy of $43,000 a year? Bump that up by a couple of grand I'd say and start cutting the red tape and overheads generated by CASA for GA Operators to help adjust for it and you'll start turning the tide I'd say.
Surely CASA should be audited and have it figured out how much it costs for a GA Operator on Average, find where those costs are coming from and figure out how they can be reduced. This should be simple for them to justify, they're promoting GA which means Pilots are able to get more experience before moving on and are paid better which means no longer having to work second jobs and flying with their eyeballs hanging out their heads just to make ends meet!!