It probably was. It's not as clear cut as the case of the waiter, but I don't think my current work creates a benefit for the taxpayer as large as the subsidy I received. When I was still an academic, I created a larger external benefit [1], but it's far from clear that it was positive.
If subsidies were abolished, I expect college would become cheaper and more efficient, most academics would find new employment, and most marginal students would not attend college.
[1] Currently I work as a trader, and most of the benefits I provide are captured by myself and my company. None of my academic research projects have resulted in anything useful yet, though admittedly the jury is still out (people are still exploring some of the lines of inquiry I created).
I don't necessarily disagree with you about ending subsidies, but it seems as if you are trying to have your cake and eat it. Maybe I've misunderstood your position. If they were abolished, would you expect college to get cheaper and academics to tolerate a pay cut, or students to make up the shortfall by borrowing higher sums?