The evidence is that students from higher earning households are more likely to also end-up in higher earning jobs (ie.
there's not as much social mobility as was expected). At the moment those students don't get full loans, but under your scheme they would. Whereas the students in lower earning households are pretty much unaffected. So, the increased loan book comes from increasing the value of loans to higher earning students. They would therefore have to repay more than they currently do when they graduate (because currently they get free money from the bank of mum and dad). Those graduates repay 9% of their income at present. What repayment % do you estimate they will need to repay at to meet the demands of the increased loan.
The lower earning graduates can not pay more than they already do, so the extra repayment HAS to come from higher earning earning graduates. It's not that there are loans to more students... it's that the level of loans to high earners has increased. The
number of loans is
unchanged. There aren't more graduates who have to repay... just some graduates will be repaying a lot more. They happen to be the high earners. You know the ones who already have a higher tax burden.