It will be a perpetual debt at this rate unless you consistently earn over 100k/year. Only about 5-6% of the population makes this as their annual income. If you make less, the repayments won't even cover the interest.
I have a HECS debt of 50k and even with the current arrangement, it likely won't be paid off unless I make additional voluntary repayments.
Ok so it's not the interest rate that's the problem, it's the preparedness to repay that may make it perpetual. But no one says you can't pay more. Do you pay the minimum monthly repayment on a credit card too?
So yes, if you choose not to repay, there is potential of a perpetual debt. I suspect that such a person would have no qualms with this given the bizarre fact that such debts are not recoverable from the estate.