I can see a future cynical me talking about how brutal it is to lure poor students and have them take loans to pay first year tuition only to kick them out a year later with nothing to show for it, if they're not the top 1/3 for some reason.
Also, even in "free" education systems, some taxpayer is going to ask "why the hell am I paying for 2/3 of crappy students, can't you just raise the bar at the beginning, and only accept the top 1/3?"
In an ever more pacing world, we should readjust and look back, some might "sacrifice" a year, but they also learn valuable experience so not all is lost.
Today, when people's work time can last 50 years easily, what is a year or more? Let people "search for themselves". Let them try out the hard things, let them explore and value experience, realize if something is for them or isn't.
In the end, we learn most from our mistakes, not successes.
That's only if you do nothing else for the rest of the year...