This has virtually nothing to do with opportunities/wealth and instead down to parenting. Unfortunately you can't just take kids of parents.
Known people from absolutely dive estates, single parent and zero financial help. Yet they can make it. Thanks to decent parenting.
But how do you build good parents?
How good a parent you are is related to how good a start in life you had, which corresponds in part to how well off you were. There are exceptions yes (and I've met some too), but that's what they are, exceptions.