system
A chat on subreddit /r/NoStupidQuestions
human
I don’t think people just become conservative out of thin air. I think the goal posts that define liberalism and conservatism move, and their once liberal views are now viewed as more moderate, or conservative.
gpt
I agree.  This isn't the only reason, but it changes.   Fpr example, my grandmother was very progressive about race and homosexuality.  I heard her berate her peers about being racist or homophobic.  

But she did not understand trans people at all, thought they were confused about being gay.  She also would buy into (non negative) racial stereotypes all the time.  Trans rights and "microaggressions" were not issues of her time, and the progressivism she learned in her youth  didn't translate to then.