When we're discussing policy for our society however it's too easy to blame people for the choices they made so we don't have to think harder. The world's complexity is beyond what the humans brain can hold at any single time. Some people are dealt bad hands, born in a difficult family, born in a body that slow them down or drag them down. Some people make one bad choice (even something mild like a financially unprofitable carrer choice) at 18 because millions of parameters that played since their birth compulsed their brain to make that choice at that moment in their life. Not even mentioning meeting the wrong people. You can do everything well and cross the path of someone who breaks you.
Truly and without getting too philosophical,looking back and learning about people's stories I've come to realize that we have little agency and by the time we understand how the world works and what we should have done instead it's often too late to change the outcome drastically.
To tie it all back to the topic of this thread, the 19 year old who's been pushed by his parents all his life to get good grades, study well, get involved in the right extracurriculars, ends up at Stanford, starts a startup because that's what people do around him, is told to apply to YC, is accepted, is taken care of by YC, tell me how much is he responsible for his success?