Do you think we could first try serious high school for all? From Does the Academic Left Understand Human Nature?:
If you have college for all but don’t dumb down the standards, the dropout rate will stagger the imagination. If you have college for all and lower standards so that most can earn a degree, then you devalue college by transforming it into something more like a longer and (much) more expensive high school. So then the high-achievers will feel an even greater imperative to go to the next level. High school becomes middle school, college becomes high school, graduate school becomes college, and our prolonged adolescence continues and worsens.
Much of college has already become glorified and expensive high school. See An Academic Hit Man Brings More Bad News.