Australia's debt is in the form of HECS/HELP. It's indexed to inflation, and integrated into the tax system such that it's only repaid on income over a minimum threshold. The first threshold is 1% of income above $56k. The last threshold is 10% of income above $166k.

My understanding is that US student loans accrue interest at rates above inflation. They do have repayment plans based on income, but because the interest rate is higher than wage growth, the debt just keeps growing if you're on these plans. They also don't have progressive thresholds like we do and the repayments tend to be higher.

Australia has a similar but less severe problem. Inflation and wage growth are closer together but they aren't the same. Still, the situation in the US seems worse.