It is important to remember more money does not equal more love, however more money helps buy support and therapies that can help SEN children.
I don't think that the state education system is a good fit for many children and therefore the children that 40 or 50 years ago needed a teacher to hold their hand or explain things in a different way is now lost to the SEN system. These children are often academically bright, yet require more social and emotional care.
Last week, I came across a lady who had a child with a very similar presentation of ASC to my own. She seemed completely bogged down in the system and referenced problems with her child's primary several times within the 30 or so minutes of interaction. She had a notebook and was even making notes about what I was saying too. I wondered whether she had no support for herself and this was why she was struggling so much.
I found myself thinking that I was very lucky to have had the money, support and balls to force adjustments for my child who happens to fit the above bright but needs help socially category.
We happened to choose a primary school which was small, caring and gave most children the time of their life. Added costs are however requires for trips and extras. If I had to work a fulltime job or was dependent on benefits and used wrap around care, my DCs outcome would have been much poorer.
We found a naice, small indie which will cater to the social emotion needs of DC for senior school. They had to pass an entrance exam and therefore was tutored, again at additional cost. Otherwise, they'd be at the mercy of the local state secondary. I'd literally have remortgaged my house to prevent that outcome.
So in conclusion, yes, more articulate/middle class/highly educated parents achieve the desired outcomes to help their children. Not because working class parents are feckless, but because the state education system is designed to create round pegs for round holes. Its not broken, its just wrong.