Different market, but Zone2-1 (a perfectly common commute) is £5.80 return = AU$10.18 in London.

Considering Zone2 is aspirational for many, not to mention those who'd rather live in the home counties (i.e. 'suburbs' I suppose) and get a certainly much more expensive train in (and then the tube) I don't find $12 questionable at all. But markets do differ! Interested to hear if that really is outrageous sounding in Australia.