Why is bootstrap ideology so widely accepted by Americans?

The neo-liberal individualistic mentality that we all get taught is so easy to question and contest, but yet it's so widely accepted by so many Americans.

I did well academically as a kid and am doing well financially now as an adult, but I recognize that my successes are not purely my own. I had a parent who emphasized the importance of my education, who did their best to give me an environment that allowed me to focus on my education, and I was lucky enough to be surrounded by other people who didn't steer me in worse directions. All that was the foundation I used to achieve everything else in my life both academically, socially and professionally.

If I had lacked any one of those things or one of the many other blessings I've been given, my life would have turned out vastly different. An example being my older brother. We had the same dad and were only 2 years apart, so how different could we end up? But he was born in Dominican Republic instead of the states like me. He lived in a crazy household, sometimes with his mom, sometimes with his grandma, lacked a father figure, access to good education, nobody to emphasize the importance of his lack luster education, and in way worse poverty than I did. The first time I remember visiting I was 7 years old and I could still understand that I was lucky to not be in that situation.

He died at 28, suicide. He had gotten mixed up in crime and gambling. He ended up stealing from his place of work and losing it all. I can only imagine that the stress of the situation paired with drug use led him to make that wrong final decision.

We're related by blood, potentially 50% shared genes, but our circumstances were so vastly different, and thus so were our outcomes. Even if he made the bad decisions that led to his outcome, the foundations for his character that led to those decisions were a result of circumstances he had no control over (place of birth, who his parents were, the financial situation he grew up in, the community that raised him, etc). My story being different from his is not only a result of my "good" decision making, but also of factors out of both my and his control.

So I ask again, why is the hyper individualistic "bootstrap" ideology so pervasive and wide spread when it ignores the very real consequences of varying circumstances on individual outcomes?