I appreciate this point. But I don't think it's about setting extremely high standards across the board and leaving those who can't keep up behind.

For me it's about losing the mindset that children of certain ages are incapable of doing certain things and deliberately holding them back (with nothing but the best intentions I'm sure).

I have a friend who is a published poet and prosaic genius. But she literally cannot solve 2x=4. I'm not being hyperbolic.

Pushing her in math as a child would probably have been catastrophic for her emotional well being. But limiting her in other skill sets (like literature) would be equally catastrophic in terms of wasted potential (and the well being that comes with excelling at something you care about).