To answer your question: well the answer is that those things HAVE happened, exactly as I theorize -you're doing the math wrong (by leaving out other variables).

The loss in jobs in recent years were due to a depressed economy - and they were overwhelmingly low-paid, low-education jobs that were lost. High-paid jobs for graduates have gone up - and in fact salaries in those jobs are skyrocketing due to a shortage of people forcing companies to seriously compete for candidates. I personally have increased my salary by over 30% in 2 years due to companies actively fighting over my services ! 

So you're using the wrong numbers. More-over even the other jobs it had a positive effect on. Without those graduates the job losses of this recessed economy would have been much, MUCH worse.

Finally - you haven't accounted for the "add to the taxbase" versus  "lifetime being subsidized BY the taxbase" numbers.
Everyone costs tax, we need as many people as possible earning enough to PAY taxes.