However, often it is not known until after they attend college whether they will succeed. High school academic record and test scores can only predict percentage chance of success, not guarantee success or failure. And those who attend college after gap years (e.g. work, military service) may not be the same as right after high school in terms of chance of college success.
Of course, the reality these days is that attending and completing college is usually more about parental financial support, rather than one’s own academic merit.