The Declaration of Independence says that "all men are created equal". It nowhere implies that (after they are created) they will remain equal. Some will produce and prosper, some will not and be poor. Some will study, and some remain ignorant. Some will be lucky, others not. Nowhere does it even imply equality of outcome. We have the right to "the pursuit of happiness", not guaranteed happiness. This pursuit, as with any striving, will have as many outcomes as there are individuals.