As others have said, it’s difficult to make generalisation and we can only speak of our own personal/children’s experience and anecdotes from those we know.
So my tuppence worth... I went to a lovely primary school (or that was my opinion through the eyes of a child).
The school was single form, we had concrete playground, a large field and adventure playground we used in the summer, a nature area with a pond and an outdoor 15m pool. This was a state school and we just happened to live in the catchment area - my parents had no concept of this, it was pure luck. Sounds bloody amazing and my memories are very much of a lovely childhood.
I was naturally bright, motivated, passed 11+, went to grammar, sailed through, went to university and studied a highly competitive degree and all’s good.
My children go to private school - started in reception.
They have all the above plus opportunities I never had - orchestra, strings/woodwind/percussion/piano/drums/rock clubs, choir, dedicated music lessons, drama,. PE is hockey, netball, tennis, cricket, athletics, football not climbing ropes in vest & knickers. Design technology- doing work in Y3 that I did in Y7.
They love doing sport, even though they are not brilliant at it. Want to try out for squads, excited about sports day, competitions within the school and between schools.
In secondary, I had no idea where to begin with the sports and no really coaching, squads or competitive sports. There is a high drop out rate of girls from sports when they hit puberty and so being introduced to sports/games for the first time at age 11 is not really going to cut it for many.
There was an orchestra which anyone could sign up to but I played piano so that didn’t work. No other opportunities to join a music club.
This may make no difference to their lives long term or this could give them the chance to develop a hobby, passion or career. Who knows? Maybe it’ll be 1000s down the drain?
I am pretty sure that if my DCs local school was just like the one I remember from my childhood, I would be delighted to send them there especially if their life turned out the way mine did in terms of education and career. But now I see what they have, I would find it difficult not to chose the same again.