I think over time what seems reasonable has been stretched. Given that you don't have any collateral with this debt, $30k seems extremely deep under water to me, coming from a generation where I was able to pay off all my student debt with a relatively low-paying job within a couple of years.
> The usual rule is that student debt shouldn't exceed your expected first year income
Was this rule made by the same people who made the rule about how much to spend on an engagement ring?
If you go to Stanford and then get a job at Google where your signing bonus is $30k cash after tax, then yeah maybe it all adds up.