Do you have anything you can cite that supports your point about this being a back channel immigration method?
I live in a city that has a huge number Chinese students, who I regularly see coming and going from the campuses. Not all top universities, either. It does seem to me like these foreign student communities can be overly insular but I've never seen any evidence that they're illegally overstaying at any scale. As they generally come from wealthy backgrounds and societies that heavily emphasise family values, I am skeptical that they'd get higher quality of life in the UK than their home countries.
the goal is legal residency, not illegal overstaying. the universities offer the path of: pay money, get a visa. by not teaching anything, the "students" are free to go work and earn back the outrageous tuition fees, or if they're rich enough, just go enjoy life around europe.
free (long term) movement/immigration for the people to anywhere desirable is dead in the modern world, you generally need to pay (golden visas, "education") or be paid (work visas).
The vast majority of Chinese students do not plan on migrating to the UK. They usually do it so they can complete a Masters in 1 year instead of the 2 years required by Chinese universities. Having an international degree also holds weight in the domestic job market.
The visa is (a) not permanent and (b) only valid for the UK, which was never in Schengen; if you are a non-EU national you need to get a visa for each European country you plan to visit, separately, according to their rules.
I live in a city that has a huge number Chinese students, who I regularly see coming and going from the campuses. Not all top universities, either. It does seem to me like these foreign student communities can be overly insular but I've never seen any evidence that they're illegally overstaying at any scale. As they generally come from wealthy backgrounds and societies that heavily emphasise family values, I am skeptical that they'd get higher quality of life in the UK than their home countries.