Those don't include private loans which can be co-signed by parents if needed, nor do they include PLUS loans where parents also take out loans. Colleges are also quite helpful in what you need to do to be declared independent for financial aide purposes, which almost doubles that limit.
They do have protections in bankruptcy as student loans though so it isn't a normal unsecured risk for lenders. They're also not hard to get, which goes back to the point of easy money inflates tuition.
Graduate students are where it gets wild though.