It's not a case of thinking they are 'better' than other people's kids - although some child are just cleverer, or better at kicking a football, or singing, or drawing. These things are quantifiable after all.
I do the best for my child because she is MY child. Other people's kids don't factor in my thinking - in the same way that I don't expect my child to factor in theirs.
The whole point of working is surely to afford the nicest life - house, holidays, experiences and for lots of people those nice experiences mean striving for the best educational experiences they can offer.
Society will NEVER be equal because people aren't equal. That may not be 'fair' but it's reality. Not everyone has the genetics to play football in the premier division - does that mean that nobody should be allowed to progress beyond the local 5-aside?
Given the state of current state education - in particular things like support for SEN - we should be incentivising people to opt out of state and leave more resources for those who don't have options.