Very similar experience to pag and holy here. No. 8 of 9. My parents had completely given up even pretending to care by the time the youngest of us arrived. They started out as educated,wealthy interested parents and ended up tired, uninterested and poor. The youngest of us were dragged up. My oldest sister snd brother who assumed far too much responsibility for us, but had benefited from the original interest, money and time moved on to university and we were left to our in devices. Benign neglect.
Now that I have my own children I'm quote cross about how little interest they took in my life. They couldn't tell you what I studied at uni, never helped out financially and never came to see my graduate from anything.
I agree with a pp, those with large families perhaps have a different viewpoint to their children. I know my parents certainly had no idea how we feel about it. If asked they would trot out a "Waltons mountain" line.
All of that said, when my parents were terminally ill, having a large number of siblings certainly made it easier. Bar one sister I am very very close to my other siblings. We genuinely love each other's company and have frequently forgone friendships in favour of hanging out with each other.
I would not recommend a lrage family unless you have an enormous income, multiple staff and the patience of a saint.