This assumes that every college grad is guaranteed a decent starting income. It seems that on average new grads are struggling more now than they used to to get jobs in their fields, especially higher paying jobs. And that perception is probably magnified by internet horror stories such as every 3rd post on r/cscareers.

Yes this kind of math doesn’t make sense in places and industries where pay is not high and job prospects are difficult. Like liberal arts. Or third world countries.

And that is the point: do the math that assesses the incomes correctly and many people won’t see as college as sensible for those professions.