I think that's a very uneducated thing to say. Obviously, films often have relevance to the decade that they are made within, but techniques and such are popularized in such a manner that they begin to feed into the hive-mind of directors across decades. You can say, a film by itself does not age. It will always be the same script but I see it how you see a film for the second time. You notice things, you see things that you've not seen before.
Symbology often has relevance past a film's 'finite' legacy; but more than likely, new thematics and such will be unearthed across decades by new critics and generally full communities attempting to analyse films.
This is an entirely different form of entertainment to what I usually specialise in (videogames) but I think it rings true here. Games such as Shadow of the Colossus were seen as new and presented such alien exhibits of game design that it was slightly dismissed for the time it came into. I didn't see it as my favourite videogame of all time, up until I revisited it later and saw the double-meaning behind everything. Now there's a new surge in the gaming machine that tells us that games can be something more than just a progressive source of entertainment; but have long-lasting appeal and emotional connection with those who play them. Shadow of the Colossus aged very well in this instance then, and I see this as the same with films. As new critical points are discovered, more films are drawn out, new comparisons can be made and you can dive deeper into the rabbit hole of films.
This is a wild guess and quite a rude accusation, but I've doubt you've ever taken a Media Studies class.









