A vague ambiguous nebulous nothing-burger.
People who don't understand Economics always say that.
For the longest time, 95% of the population -- including children -- were engage in agriculture. Why?
Um, so you don't starve to death and so you have something to trade to improve your Standard of Living.
Thanks to technological advances, it eventually only required 90% of your population -- including children -- to work in agriculture. Why?
Um, again, so you don't starve to death and so you might have something to trade to enhance your Standard of Living.
When a country makes that leap from a 1st Level Economy to a 2nd Level Economy, it requires an enormous amount of labor, more labor than a population generally has and that is why children must work, at least initially.
The fatal flaw in your nonsensical ranting is "skilled labor."
Do children possess skilled labor? The operand is skilled.
No, they do not, which leads us to another important facet that your fatally flawed rantings ignore and that is Birth Rate.
Expansion through the 2nd Level Economy requires ancillary services, which is why GDP growth is generally 8% to 15% per quarter.
A work-force educated to the 4th or 6th Grade doesn't get it and neither does the 8th Grade. You need people educated to the 10th Grade and then you need people with high school diplomas.
Staying in school delays marriage which reduces Birth Rate.
But for the ancillary services like management, administration, supervision, accounting, legal, insurance, finance, logistics, research, development, testing, design, engineering, architecture, drafting etc etc etc you need college educated workers.
That delays marriage even longer and reduces the Birth Rate even more.
If you do doubt, might I suggest you avail yourself of the US Census Bureau website so you can visualize the drastic drop in Birth Rate in the US long before birth control became available in the mid-1960s.
Your claim that children would be working is absurdly farcical.
While I'm on the topic, you're probably one of those who think over-population is problem (and it is, but only in your head).
The US will not develop sub-Saharan Africa, but the good news is that China will.
As the sub-Saharan States move from the Zero and 1st Level Economies into the 2nd Level Economy, they will need an educated workforce which means more schools, better schools and people staying in school longer and delaying marriage which will reduce the birth rate exactly in the same way it did for Western Europe, the US and Canada.
So, get over it already.