Well, I agreed that's a more subtle take on the whole thing.

A hard-nosed take aiming purelly for maximization of tax take in this domain, requires finding a balance between the additional revenue that well educated people will bring to the taxman (not just directly but also indirectly as, for example, they enable other jobs to add more value) vs the money spent now by the taxman to educate them. This purelly economic take does bring considerations about "what is the future tax value of different degrees" and requires that pupil selection uses as meritocratic as possible criteria - and access to money is definitelly not and indication of merit for a degree - so that university education delivers the best people for the job at the end hence maximizing wealth production and thus tax revenue.

Clearly higher-education for everybody for free would not be tax-optimal but that doesn't mean that not-universal higher-education with money as the main criteria to filter access to those limited places is better. Certainly the current method in the US of restricted access through ridiculously high fees and a statistically meaningless schollarship mechanism (outside sports schollarships it's minimal and training athletes is seldom justifiable by economics) to pull it a little bit away from the pure monetary filtering criteria, is also far from delivering economically optimal results and hence a higher return.

Somehow other countries manage to have a huge fraction of the population have access to higher education for pretty modest or even no fees whilst still having a higher per-capita income than the US and require importing far fewer, if any, degree-holding immigrants to generate that higher per-capita wealth, so that would indicate that what's done in the US now is not at all optimal.

It's valid to look at higher education as something that consumes resources hence cannot be available with no restrictions whatsoever, but if there is indeed limited access and your objective is the best possible return for the country's economy or even just the taxman, managing the scarcity that comes from the existence of a limit on the provision of it via a pure pricing mechanism won't deliver the best economic return for the country or even the taxman because theirs is a strategic interest that goes far beyond maximizing the revenue of universities, which is the only thing that higher university fees optimize.

There might be an optimal fee point for the taxman and the economy, which is not zero, but exceeding it reduces the future returns for both because it makes increasing numbers of people who are "the best for the job" in those high value added domains requiring such a degree to not take the degree, so less competent people end up doing the job hence less wealth gets produced and taxed.