system
A chat on subreddit /r/NoStupidQuestions
human
Tldr: The young tend to want change. The old tend to want stability or comfort.

Most people aren't aiming for change at the age of 55. They're aiming to settle down and to not have to worry about instability ruining what they have. 

On the other hand, the young tend to be much more accepting of change because they're the ones driving most of it; It's their world. 

Society is ever changing, so it's inevitable that newer generations are moving away from what the previous ones were aiming for.
gpt
Broadly speaking, yes, you're right, but you're missing the point of why especially nowadays young people tend to stay progressive and leftist. Because of ever-increasing income inequalities, inflation, bad housing markets in a majority of (Western) cities and impending climate disaster, young people are realising that they won't be able to retire and receive the benefits of the system that is currently supporting the boomer retirees - hell, population growth stagnation means that social welfare is going to be a bigger puzzle than ever in the future. If we want what boomers have later on in life then we need serious change which only progressivism is able to promise us.