The age factor thing someone quoted is bullshit. A good film is a good film no matter when it was made or when you saw it.
Not true at all.
Some films simply don't hold up over time; TWOK is a very 80s movie in many stylistic respects. It's entered popular culture for the most part as a source of material for joke writers - fondly-made jokes in most instances, but grist for humor is nonetheless the film's primary resonance for most non-trekkies.