How much does differentiation/learning at school really matter?

[mrsshears]

I'm posting this as more of a discussion really as it's something i have been thinking about alot recently.
My daughter is 5 and on the 99.9th percentile for IQ, she is not differentiated for or challenged at school and never likely to be at her level (if she stays at her current school).
My question is if the child is generally happy how much does this really matter? do they loose it if they don't use it? can school just be used as a social exercise and learning/stimulation be done at home?
I would be really interested to hear your thoughts on this subject.

No books to take home? Er, why not?
Dd2 was reading c s Lewis before she started school lol, they still managed to walk her to other year groups so that she could take books home from their shelves. It's not difficult.

I was identified as Gifted as a child, IQ somewhere around top 0.01%tile.
Probably just proves what bollux IQ tests are, given my surfeit of typos.

I think it's horsesh*t that such clever kids don't learn to work hard because "everything" comes easy to them. And I heard that myth a lot when I was growing up, which I imagine made it easy for my parents to not address the real reasons why I didn't cope well, why I didn't have actual confidence or good self-esteem. Nobody is truly great at everything. There are literally dozens of things I've had to work hard at & many of them I will never be good at in spite of my best efforts. In life, there are no end of opportunities to work hard at worthwhile things.

I have a gut feeling that it is expecting too much of a school, at least wrt helping children learn to work hard, to think that's somehow mostly the school's job. Ime, the ability to work hard at things comes out of having general confidence, and optimism. Things that come from a large number of factors, most of them happening out of school.

Much of what Rabbitstew said is good.