There is no inherent right to university education. It is a service and people should have to pay for it should they desire it. The role of the government is to provide individuals with necessities, hence why primary and secondary education is free. University is not essential for an individual to be a functioning member of society so there is no obligation on the government.
Secondly, there are ways in which meritocracy is prioritised over privilege in creating access to university. Students who perform well academically can get financial aid, scholarships and bursaries which enable them to continue their education. Even though alternative funding methods are imperfect, that is an argument for improving them not one for making it the responsibility of the state to ensure everyone can go to university.