I was the elder of two; a perfect family, one girl, one boy, 2 years apart. Brother was the Golden Child. I spent my childhood feeling that with two children you have a Favourite and an Unfavourite. DM expected me to look after DB, then I got into trouble when he wouldn't behave. There were issues in my teens and young adulthood when I wished there had been a third sibling to help, when DB was a total shit.
DM was also the elder sister of a Golden Child, yet repeated the pattern with us. DF was the eldest of 3 and didn't seem to have any issues. Neither of them had time for me in my teens and young adulthood; they were firmly fixated on themselves and their own hobbies.
I should have had counselling before I had my children but it wasn't available. I was determined not to repeat my upbringing. I planned to have just one child, but when she was born I realised that I was too anxious to have just one. I realised I would expect too much from her (DF was a perfectionist) and put too much pressure on her, so we decided to have 3.
DC2 was a boy, so now we had the same pattern as my family. Girl, boy, 2 years apart. Worst possible combination. Again, no counselling, which would have been the best option. Had DC3.
DC4 wasn't planned. I'd gone back to work, house wasn't big enough, car not big enough. No affordable 7 seaters in those days. We didn't claim benefits, but both worked around them. We were lucky that FIL retired and helped us out with childcare because we couldn't afford more than playgroup, but in the main we worked shifts around each other so we didn't need formal childcare. At no time did we ever expect the older ones to bring up the younger. There were less than 6 years between the 4 of them.
They are now adults. All working, none on benefits. They are genuinely close and have a relationship independent of us. DD moved away as soon as she was able, and doesn't want DC, so I probably made as many mistakes as my DPs did. But then my niece, raised as an only and very close to her DM, doesn't want DC either.
We have 2 DGC and I feel it's unlikely there will be (m)any more. DGC are a girl/boy pair, and the birth of the boy triggered my MH issues. Their DF feels he had a good childhood and that he had good parents who were always there for him, so I did something right.
People will do what they feel is right for them, until a future government decides to intervene and decree who can have children and how many. It really is nobody else's business, unless you are expecting somebody else to directly pay for your choice. (I don't mean NHS/schools, since none of us knows what is coming).