Some films have a fashionable look, and look great at the time but 20 years later feels dated and old. So many 80s movies feel stuck in the 80s. But I strongly believe that a beautiful movie will never go out of style.
"Timeless" isn't the right word. Because what's "timeless"? This isn't a diamond necklace. But not being able look at a movie and say what decade it was made in is actually a high compliment. The Last of the Mohicans could have been made in the 50s and it could have been made a year ago.