The debt I've seen my peers saddled with has typically been 6-10%, issued mostly in the recession/post-recession years of low interest rates. It seems like exceedingly high interest to me when mortgages and car loans are half as much.
a better comparison for an unsecured loan would be a credit card. please let me know if you find a credit card with anything near a 10% interest rate. afaik, the best rates are around 14% and only go to people with very good credit.
a private student loan is not a particularly safe debt to issue. even though the loan cannot be discharged, there is still a substantial risk that the borrower will never be able to pay it back. credit cards and personal loans are a pretty good comparison IMO, as the main difference is the fact that student loans cannot be discharged. this is in fact priced in already; even private student loans have much lower interest rates than any other kind of unsecured loan.