Anastaisia, I totally agree with you re delaying formal education to 6/7 yrs old. Here in Italy primary school starts at 6, and children learn to read pretty quickly then (while I remember my ds, who started reception at 4.5 in the UK wasn't remotely interested in letters etc).
I also would like to point out that the ability to read (early) seems to be an obsession of the UK. As I said, Italy offers 3 yrs of free nursery school, but by no means are the children "forced" to learn to read. They are too busy doing creative and manual activities! (which is good, as creativity is often neglected at primary school )
Also, I think cultural attitudes towards the benefits of nursery schools change from country to country. Here in Italy our nursery schools are generally considered very good and primary school teachers are often able to recognize the children who come from a "good" nursery school, where they've learnt to work in groups, cooperate with each other etc etc.
As for involved parents, I do agree with you.
However, I still think it is important for a pre school child to have a few hrs in a different environment, doing different activities, managing his/her own friendships, learning new things.
I consider myself to be an attentive and involved parent, but by no means I'd be able to offer my children the range of activities they do/did at nursery school. It's a question of time, and my personal level of creativity (very low).