I resonate with the first paragraph. Those people raised with beliefs of a time that does not exist anymore happen to be very conservative and refuse to see the change.

Nice food for thoughts.

So for exemple the diaspora that left Iran when the Shah left is probably still thinking of Iran as it was at the time.

Without generalizing it most probably mean the same thing for the Jewish that stayed conservative through the exile.

And so on with every person that migrate, bringing the culture of a bygone era with us

Is it the past travelling in our present?

And all change is always for the better, is always progress, some even say..

In fairness, for you to say those beliefs aren't valid now is equally conservative - things will change and maybe in the direction of their beliefs, in part because of what they do. That's how change happens - some people with a different vision persevere from being rejected to being accepted.

They are conservative about time X, and in your comment is conservative about time Y (which happens to be now).