This is how it works in Australia and it works very well IMO.

It also indexes with inflation so that there isn't a major stress if you graduate with a low paying job and work your way up to a higher salary.

This does mean its everyone's lowest priority to pay off, but you can't reasonably avoid paying it other than not making an income.

It works exactly like this in the US. People who aren't currently in college just aren't aware of it.

This is how it works in Germany. Tuition is (almsot) free, but you get an allowance (up to aprox €850 IIRC) every month, if you and your parents don't have a high income. In most German states you a) only have to pay back up to €10k of that and you only have to pay if you make more than a pretty high number that I forgot AND you have a graceperiod of several years before you even to start paying after you leave uni. Consequently, I know nobody who has difficulty making payments.

All federal student loans work exactly like this, and Federal loans account for 90% of all loan disbursements.