This makes no sense - you are proposing restricting the options of high performers so that they don't make self interested choices. Why not restrict the choices of low performers instead?
My point, as applied to this case, is that giving the option of "smart-only schools" will predictably lead to people taking it, which may lead to issues described by 'habosa here: https://news.ycombinator.com/item?id=13483591. It's a reasonable question to ask if this is what is beneficial to the society (including its economy), and if the answer is no, then not giving such an option in a first place is an entirely logical approach.