Immigrants from 3rd world countries with zero formal education, zero real family experience with building wealth, save money like crazy in the US.
There's "building wealth" and there's just responsible money handling. Normal families handle money in responsible manner (have savings, avoid debt etc.) and such behaviors are passed to children. Pathological families can be doing all kinds of crazy things with their money - take up expensive debt for frivolous reasons, spend the whole salary up front and go hungry until the next one arrives, lose houses over small things (e.g. a guy in my family traded a large apartment for a much smaller one, a bottle of vodka and a dog) etc. Their lives is chaos, and that includes the financial aspect of it. A child in such conditions really can have no idea that it's not a normal way to handle money, and that it can be done much better.