Is this just the stereotype?
I went to a school that cost 18k a year (15 years ago). It’s now 24k a year.
There were wealthy people there. But also many ‘normal’ people. At least 40% fell into that category. People who lived on estates, drove modest cars, skipped holidays and ate cheaply.
They made a choice to spend their money on private education. For context, two of my closest friends have dc in private. They live off 450 a month after paying fees. They are not high earners.
Not everyone has endless wealth. Some are just happy to make the sacrifice. I find it strange people don’t seem to get that and makes me wonder how lacking in knowledge you must be to have that view of the private sector.