I think different people pay for different things. We started our older 2 boys in the state sector then moved them after the infants. However, unlike some of the posters above, I discounted any schools with classes of 15 or less. My boys were in classes of 22-24 for most of the prep years.
I disagree with @MaisyPops that good state schools can match good independent schools when it comes to extra curricular. Many state primaries are getting similar results academically but I’ve never seen a state school that can match a good private school in terms of facilities and extra curricular. At secondary there isn’t the funding and at primary it’s not only funding but often space and staffing levels too. 2hours of music a week and 3hours of sport. Art curriculum that includes use of the kiln, painting on canvas, textiles, stained glass, laser art etc. Sport that includes 1h of swimming a wk in the sch pool, rounders, hockey, gymnastics, dance, football, tag rugby, climbing and athletics all taught by dedicated PE specialists and all offered as extra curricular as well and timetabled. In the infants, which only my DS3 benefitted from, the have reading club, habitat club, allotment club, construction club, art&craft group. They can learn almost any instrument of their choosing. There is also drama and LAMDA. They packed so much into each day and by the time the older ones reached senior school they have developed real passion for their chosen sports and instruments. It also forstered an inclination to be busy. So at weekends they’re up and out doing stuff which is the biggest difference I see between my children and those of friends who kept theirs in the state sector. My boys may come out with similar grades to those who went to our local high achieving comp but for me it’s how their school has shaped them as people that I’m most grateful for. Like all teenagers they’re interested in their phones but thankfully, unlike a lots of other teenagers, their lives don’t revolve around them.