If you were born poor in a society which sees part of your genetics as undesirable or outright criminal—none of which were your choice—you’ll find yourself in very dire straits and changing your situation—heck, even knowing a better life is possible—will be extremely difficult.
It is not reasonable to tell a child sold into slavery or forced to be a soldier to “make their own luck”, that “society, and the wider economy are for everyone to navigate”. A person in the eye of storm and another in calm waters cannot navigate the same way.
People who firmly believe they above all “made their own luck” are the ones who had such a large amount of it outside their control they don’t even realise how much of it they had, like a fish unable to perceive the water.