Well I don't blame lack of Christian values or lack of stable families, I blame lack of transmitting the value of education by parents to children, which can occur for many reasons, some correlated to lack of stable families.

The most important factor in school success in fact is size of vocabulary at the start of school. 

If parents are too preoccupied with their problematic love lives, or lack the cultural capital themselves, to make sure the kids get an early, good grounding in language skills, the kids will struggle in school, fall behind in reading, probably develop a hatred of it, etc.. It then becomes very difficult to catch up.

If you can barely graduate from high school, that makes attaining a university education pretty much moot, no matter how cheap.

The problem isn't getting everyone a university education, it is making sure there are decent alternatives for people who can't get one.