I don't fully disagree (lots of people never change) but I've experienced (what appear to me at least) to be significant changes to my behavior that have now be

I don't fully disagree (lots of people never change) but I've experienced (what appear to me at least) to be significant changes to my behavior that have now been sustained for a long period of time (many years). How can you square your comment with people like me who seem to have done it? Am I mistaken on actually changing, like it's all environment or something?