Yes, that’s unreasonable. Some private schools aren’t that great.
I had a boyfriend who’d been to private school.
Most perks were of private school were class size (often larger than my grammar school class sizes) and extracurricular activities. I actually did more by choice outside school and tried skiing, ice-skating, gymnastics, swimming and diving, flute, cello and drums, fencing, trampolining, rock climbing, shooting, ball sports, basket ball camp with a local team player as coach, loads of craft groups, hiking, orienteering and DofE. And many types of dancing. All sorts, and for much less than private school. I guess my average cost was £25 weekly as I went between activity types.
My boyfriend was also offered less languages (my school did 5, including Latin). French and one or 2others of your choice was the start.
We were taught to think at grammar school and he was taught to pass exams (so we’re we of course).
i always joked they had proper equipment like dissection trays while we used newspaper, learning to make the best of what was available and maybe reading the news too (not available on proper shiny dissection tray).
In this one example it would appear my grammar school and outside school extracurriculars led me to have a better education at a fraction of the cost.
Many private schools are waaaay better especially than state school, but anyone who has the inclination to research can see the benefits and costs of different individual schools as well as trends of private/state/grammar/home Ed//academy/religious school/Steiner etc.