The article states nothing of the cost inefficiency, that is cost of producing the good or service. Instead, the article tries to claim that the price of education makes it a questionable investment, given the monetary returns.
Higher education can and is being delivered at reasonable costs across much of the developed world, with many countries choosing to have taxpayers carry the burden of funding education.
This common-pool resource approach (that is non-excludable, but still rivalrous) to education does not prevent private education that exists as a private good (that is both excludable and rivalrous), but it does ensure a baseline.
As a society, we have decided that certain things should not be left to market forces, because either the outcomes are morally objectionable to the majority of the population (welfare for example), or we see a greater overall economic return on investment by doing it en mass (healthcare, education, etc).
Healthcare is especially interesting - if we leave it completely to market, we will likely have return of pandemics that are currently being kept at by via vaccinations and mass treatment. If we allow an economic driver to avoid this care, the diseases we largely think of as extinct can return.
Education can be thought of in the same view - if we provide everyone with a solid baseline, and support future growth regardless of economic background, it is likely that we will reduce the negative effects lack of education currently has on society. Removing the debts will also help and provide a huge social benefit, as well as spur additional economic activity.