First, it's a complimentary insurance meaning that it's for extras that people otherwise pay out of pocket or go without like dental, private hospital rooms, etc. It doesn't cover the really expensive unpredictable things like major surgery, cancer treatment. The basics (eg GP visits) and the big expenses are covered by medicare.
Second, it is subsidized from both ends. The insurance companies get paid by the commonwealth and the expense is mostly tax deductible.
You really can't use the cost to us as a measure of what it costs to run.
