Student tuition does not fund research (at least in STEM in the US). DARPA, NSF, NIH etc. fund research. Professors at research institutions are to some extent evaluated based on the the size of their research grants.
If what you said is correct (which I'm sure it is), it's only reduced my understanding (in a good way - thank you for your explanation). So - the government pays professors for their research, and then this very research is put behind a paywall, from which....publishers (?) make money?. I apologize, but it simply does not make sense to me, it seems extremely counter intuitive.
The situation exists because it just evolved into what it currently is, and until recently no one seemed to care. Before the internet for example, it made a lot of sense for publishing to be handled by a private entity. There were real marginal costs to the production and distribution of journals and demand was relatively low.
Today this is very much changed. Demand is high and marginal costs are zero. So I imagine we will move towards an open access model.