That's way too basic to be a solution. If you take from them they'll simply take it back from us by cutting jobs and services while raising fees.
We should be making it harder if not outright illegal for them to arbitrarily cut costs in the way they do i.e closing branches, offboarding atms, making workers redundant to keep up profits. They are in many ways a public service and the service component is worth protecting.
Countering this behaviour would be far more impactful to Australians and the economy than just having them hand a bag of money to the government.
Most people commenting here don't have kids. Private schools are so prolofic because the majority of public schools are so defunded and sad looking that there is a native demand for schools with... non-below average facilities which families are willing to pay for.
This country doesn't spend enough on education and instead is letting its citizens fund the education sector out of their own pockets. It's kinda criminal.
So instead of blanket banning private schools we should be funding public ones to the level that makes most private schools redundant.