Thats a bit pessimistic. I think that the majority of people are most heavily influenced by their experiences in their formative years (teasing the whole nature vs. nurture rabbit hole lol); what big challenges did you face, who did you look up to, who did your close personal relationships and friendships play out?

Reality being that as we grow older we have less and less people to help show us how to stay on a "good path" when we might falter off (whether that be gambling/substance/abuse). And achieving success and wealth only further opens the possibilities and dwindles down the safety nets in many senses.

But barring some deep seeded narcissistic/psychopathic personality disorder, I think that most kids up through 25 or so can be retrained and assimilated back into society.

I feel like getting into 30s or middle age is where your behaviors start to really solidify and your perception can become so warped you can truly lose a person.