EarringsandLipstick, I absolutely agree, teenagers for us and in our context, are way more expensive. £2000 childcare is alot, we would not have paid that in the southeast of England when DS was a baby and actually it is fewer years than the teens so a very short but expensive time if full-time. Due to inflation you can't compare childcare costs of a preschool infant with a 15 year old of 2022 as when your infant is a teenager it is very likely that it will be more expensive.
In my context I was on full pay maternity leave for a year and then didn't return to work as DH was working in the day and had to study in the evening as we had DS in our mid 20s and DH had not qualified to be an Architect at that point(many years training), plus DD arrived when DS was nearly 4 so stayed off a bit longer. It was therefore going to be more profitable in the long run for our family income for me to accommodate that as a qualified architect is much better money than an assistant and as my job was a commute to London we couldn't find childcare for those hours or afford it.
My 15 year old has an allowance of £80 a month, he may buy clothes with it but we have to buy him things like a coat and shoes on top. 11 yesr old DD has less but I buy more of her clothes with her. He didn't need an allowance as a young child and the odd toyshop figure once a month was not expensive, the same with toys for Christmas, £40 for a Peter Rabbit tree house as DD's main present, compared with a keyboard the size of a piano so that she can have piano lessons is so cheap! I spend £800 a month on family food now as my DS inhales food, he can't afford to eat less as he is lanky and very thin as it is! We usually get a takeaway or eat out once at the weekend, something the DC would not have eaten when young as too much salt annd they were in bed but now DS at least can eat a whole Thai curry for example. Clothes are retro shops so an be £20 here or there but shops like Urban Outfitters are £50 + for a sweater, Levis £100. Clothes when they were little were H&M or Boden hand me downs from relatives. That doesn't happen anymore obviously. Then the school trips £800 minimum compared too primary school residential of £300 max. School clubs cheap at primary whereas DD wants to do a theatre group that is £330 a term once they are 11, it is half that from 6- 11. DS had an expensive electric guitar for Christmas that he needed for music GCSE!
One of the biggest expenses is university as at DS's age as we need to put quite a bit of money aside for minimum £9000 a year on accommodation - it is only 3 years off!
Holidays with small children- they could fit in a family room with a sofa bed, now it is 2 separate adult hotel rooms which is loads!
You can argue about what is discretionary no doubt but then we had these things when they were little, takeaways, Holidays and food bought from the same supermarket so it wouldn't be an equal comparison as our standard of living would be worse which doesn't make any sense now that are income is alot bigger! Our income is 4.5 xs what it was when I was SAHM and DH was an assistant and yet we don't have loads spare as bigger mortgage for bigger house to accommodate two bigger children, we lived in a one bedroom flat when DS was a baby. Savings for uni, so to us and objectively teenagers are loads more.