that's not the other side of the coin. that's the other end of the extreme. there are other solutions that can accommodate both needs. the problem with splitting up schools is that kids are not always ambitions and faster, nor always slower or lazy. that changes over time. a better system needs to have the flexibility to adjust for kids as they are developing and growing. switching schools back and forth is the worst way to achieve that. i'd rather find extracurriula activities that keep the kids interested than force them to switch schools. the problem is teacher training and an inflexible education system. the ability to switch schools does not make the system any more flexible.
a better school lets you choose a more or less academic focus if that is what the kids want.
the best system btw is montesori where kids really can learn at their own pace. it is designed in such a way that even within a class different kids work on different projects. they even mix ages so that younger ambitious kids can work with older ones.
You think that's more fair to the ambitious kids when 2/3 of the class think it's cool to NOT learn anything and playing pecking order games all day?