My DC are at private school. I can only think of 2 families that go without to send their children there. The majority of us don’t cut back. We have frequent holidays abroad, the children will get house deposits / gifted properties in a lot of cases.
I think this narrative of Mr and Mrs average driving old bangers and camping in wales once every 6 years so William can go to private school is only ever trotted out on MN and rarely the true picture.
The majority at DCs school have real wealth. Not an 85k a year salary and a hefty mortgage.
Your post makes a refreshing change on Mumsnet regarding why you send your children to private school, and I think is probably true for many people in this country who do. Unfortunately plenty of people come on here and protest they are not wealthy, or privileged, and make great sacrifices to send their children to private schools.
You are saying you can comfortably afford to pay for your children to go to a school that has added extras, that even a good state school doesn't, that will hopefully enhance their school experience, so why wouldn't you? It's no different to buying a fancier car, or bigger house, really - just because you can.
I think it is the parents who choose to spend on schools, rather than other things, that expect a return on their 'investment' to justify their sacrifices. Their children are under pressure expected to come out with top grades, get places at the 'best' universities, and eventually get great, well-paid jobs.