wow, university graduates earn about 75% more than no tertiary education according to https://go8.edu.au/sites/default/fi...graduate_skills_and_national_productivity.pdf. This strengthens the argument that students should repay their education.
Further, currently the subsidies for university are covered 60% by the government. The changes proposed amount to reducing these subsidies to 50%. That still means the poorer non-tertiary educated are still forking out for other peoples privileged education.
Lastly, the shift away from CPI to government bonds provides a cap on the subsidies by ensuring the full cost of borrowings are passed on to the consumer.
You may want to read ABC's fact checker that indicate Pyne's figure of 75% is overblown.