When you say "compelled", do you mean "divulge at the threat of guaranteed jail time" as in the UK's RIPA-based mandatory key disclosure law? Wikipedia seems to indicate it'll cost you 6 months in jail: https://en.wikipedia.org/wiki/Key_disclosure_law#Australia
A year of incarcerating someone is only worth $3,400 to the government? Strange, considering that if you're going to be pedantic about money, the cost of incarceration is surely at least one order of magnitude more than that.
We're talking about a particular subset of criminal/person that can afford a computer, has the knowledge and forethought to encrypt it, and is committing a type of crime/action which makes the state want to see the encrypted contents of said computer badly enough to invoke that law. I would think that someone in that subset could easily afford $3,400.