harry potter represents a fantasy world. the Jungle reflects reality.she and her four sisters all worked. their mother didn't once she came to this country.... i'm not quite sure why.
things changed because you're required to have your children in school now til they're 16 and you get charged with child neglect if you don't. the culture changed BECAUSE of inspectors and regulations which, in turn, allowed the system to grow.
the market does not naturally take care of people. markets satisfy only the corporations that are part of it and markets do not act in the best interests of society because they are amoral.
as for The Jungle, yes it was fiction, but so was Oliver Twist. Both reflected the social realities of their days. And both would have been incredibly ugly realities to live in.
The law doesn't stop people from smoking weed, why would you think the law would stop children from skipping school and working if they had to? The culture changed because it was able to change, not because the government told it to change.
The market lifts up the standard of living for everyone.
I'm sure Harry Potter reflects some social realities of the day too, and I wouldn't necessarily want to live in a world with wizards running about doing crazy things with magic.
but its so much simpler to blur fantasy and reality. it means you don't have to address unpleasant facts.