I will try to explain this with an example... as a kid i saw every action movie and we literally counted each blows in fist fights, every high roundkick, every good looking explosion.. we were rigorous in this regard and BLIND to its actual quality.. as time passed i started to notice how each film/genre fitted into its historic continuity.. art copies life, life copies art, art copies art and life copies life... after switching to hardcore horrors/thrillers even psycho looks mundane, but to people who never seen anything like it before(same with citizen kane for the people of that era) it must have felt how seeing braveheart/rotk/t2/titanic felt for us.. a GAMECHANGER... now to give some due credit to individual judgmental thinking some classics age better than others... carpenter's the thing is immortal, goonies too, but ARE THEY? is it just me who saw them just in that right moment and is nostalgia playing tricks on me? To answer that we have to go back to ben hur, lawrence of arabia, the third man, paths of glory etc. Those are perfect as they are even tho i havent seen them before they became "old" or quaint looking.. there are examples in between/up to debate as well ofc... so that leaves us in an ungratefull spot to always step back and take a look at the big picture...
Edit: what was gamechanging in citizen kane for its era? Rosebud-
"Its not about the money"
TTVOMJ