Political online game and economic simulation

I want to suggest to introduce a tuition fee system option, that provides the universities with more funding without limiting access for the poor:

Each university has the right to raise it's own tax as a percentage of the future income of its students. the tax will be applied in addition to the state income tax for a number of years equal to the number of semesters studied starting the year after graduation and will be collected by the tax authorities for the universities.

This way the risk for the student will be eliminated, because he pays in accordance with his income.

It is a really good Idea. But not easy to implement because in our society now caste based system prevails.