I think the point of a novel is to blow things out of proportion so the point can get across However, I'm not so sure it was so far from reality. Today, high class billionaires, or even a hundred years ago in European aristocracy, wouldn't they have looked down on penny beggars? Just like a pure blood, someone who'se known nothing else (like an Earl who's the 27th Earl of the title) would look down on a mud-blood, (who like in the late 1700s, middle-class wealthy people who fought their way into nobility).

I don't think it's blown out of proportion at all, actually.