People who rate this as the greatest movie of all time have obviously never watched Paul Blart Mall Cop.
In it's day Citizen Kane pioneered a new form of film making, groundbreaking stuff, but it really doesn't stand out to me as classic entertainment... just a decent movie. I think we may be experiencing a case of the Emperor's New Clothes when it comes to calling it the best film of all time. The characters as they age begin to look ridiculous, and the story drags somewhat. Welles is held up as a cinematic genius, but the mediocre he was involved with far outweighs the brilliant stuff like A Touch of Evil or The Third Man.
At the end of the day, movies should be judged on the ability to entertain and provide enjoyment and other emotions for the watcher. This film appears to me to be judged as brilliant more on its technical merits than the latter.