Maybe I'm not understanding your point.. It appeared you were claiming that people can't willfully change their inhereted traits or habits.
Just pointing out that's the foundational belief behind eugenics.
Discussion
I don't believe our brains are blank slates. I do think many personality traits are genetic, yes. The evidence for this is high. Many studies have been done on identical twins, who were separated at birth, for instance -- and these studies have consistently shown shared behavioral traits that can't be explained by random chance in the samples.
But it doesn't follow from that, I think we should engage in eugenics. That's an insane leap.
I knew you weren't intentionally advancing a eugenics argument, but I have only heard statements like the OP from people who are.
It comes down to a personal belief in the capability of individuals to change. In my view the more someone believes they're pre-programmed the less likely they are to engage in behaviors to improve their lives.
I've seen tremendous changes in myself and others well past age 20. In my case it's difficult to attibute it to anything but Bitcoin. It's impossible to do a controlled study, but the before and after is enough imo.
I know many people who have come to bitcoin, myself included, and maintained pretty stable political views throughout the process. Which is why I suggest this belief could be a selection effect. https://en.m.wikipedia.org/wiki/Selection_bias
I can see why you would reach that conclusion.
I've noticed observable behavioral changes and shifts in perspective among people who adopt bitcoin, but it's all anecdotal at this point.
Time will tell I suppose.