That is a bit dramatic. This topic has been talked about over and over. There is no perfect system. Treat everyone the same and high potential kids suffer. Split them up by ability and you get "unfairness" criticisms.
merging school types is not about treating everyone the same, but it is about acknowledging that kids develop and you can't evaluate the ability of a child based on their performance at age 9.
as i said, i would not have made it in a tiered system because i would have been stuck in the lowest tier. my parents were to busy to argue with each other to even care and my performance suffered because of them.
those are circumstances a tiered system can't handle. a merged system that can deal with children at all levels however can, and that made the difference for me. that has nothing to do with treating all kids the same. on the contrary, it has everything to do with treating kids individually and not stuffing them in boxes like a tiered system does.
as for a perfect system, montessori gets pretty close. three years of age are grouped together in one class. that alone require that the kids in that class are not all treated the same. it allows all kids to learn at their own pace, so younger, faster kids can easily catch up to older kids and work with them or be given extra activities without disturbing other kids in the same class learning something else
Which is to say that tracking of any kind is going to end up with this, whether they are separate physical schools or separate curricula within one school.
separate physical schools however may mean that i may never see some of these friends ever again. different school routes (even if we live in the same neighborhood). no chance to meet in breaks, etc. that's a whole different world.