I DID flunk out of college - went into the military, then returned to school and 4.0'd - it's more a maturity thing than anything else - I wasn't "ready" for college on the intellectual side. I did however (regrettably) EXCEL at the social side of college.
I do agree that lots of kids are not ready straight out of HS. I wasn’t. I went one year, did pass, but didn’t do that well (had a lot of fun). Got married, had 3 kids, went back and graduated with honors. Amazing what a few years difference made.