This is exactly the system in France -- higher education is provided for free, through the highest levels. If you are French, attending the Sorbonne is free. But, in order to attend the universities, you have to pass the Baccalauréat which is highly challenging. Each year, about 20% of French high school students do not pass the Bac, meaning they repeat their last year of high school. There are other options (career/professional track programs) for students who do not want to continue on to the equivalent of a traditional four-year degree, or for those who do not pass the bac. What I observed in my year teaching in this system is that while it is an attempt to improve access for all students, in practice, many of the same inequalities exist. Poor students tend to live in neighborhoods with struggling local schools, and then end up being less likely to pass the bac or to choose baccalaureate programs in the first place. Their schools end up with the same kinds of defacto segregation along racial and economic lines that we are attempting to deal with here.