We could afford a private school if we cut back in other areas. However, we didn't go down this route because we didn't think it was worth the investment.
Firstly, I think it's a mistake to assume that private schools are automatically better than state schools. Many of my friends were privately educated, whereas I went to a state comprehensive. I do not feel that they are any better educated, more successful or happier than I am.
Our local state primary was way better in my opinion than any of the local private options. Secondary school was a bit more complicated - there were aspects of the private provision which we liked, and aspects which we didn't like. The facilities were certainly better than the state school that dd now attends, but the teaching was not. On balance, I did not feel that the private school was worth what it cost.
Secondly, our dd is the kind of child who will do well in any school. She is very bright and highly self-motivated. She also has supportive and involved parents. I am confident that we can enrich and supplement the education on offer at her state school without spending a small fortune.
A few of dd's friends from primary school went to private secondary schools. We keep in touch with them, and hear all about their experiences. Many of my friends have children in the independent sector as well. Looking at those kids always reassures me that dd is not disadvantaged in any way because of going to a state school. Quite the contrary, actually - she is positively thriving, whereas many of them are not.
Ultimately, I think it comes down to individual schools and individual children rather than any great divide between private and state. I feel that dd is in the right school for her right now, so why would I waste my money on something else?