Old scientist and young scholar

Hello,

in media there is a unifying concept of and old scientist and young scholar. The old scientist is very smart and invents spectacular things and the old scholar is some "normal" guy who things that he is a wizard.

Some examples:
Back to the Future
Rick and Morty
Fringe TV Series
Futurama

Why is that? What is the mythical context of it all?

Thanks
A scholar