I just feel at the time it was obviously so much more important. Now I can watch films like Persona or To Kill a Mockingbird and enjoy them so much more; those films were inspired by Citizen Kane, definitely, but when it comes to choosing a classic film to watch when you're in the 21st century, these films just seem to stand the test of time a lot better.
Going back to my Beatles analogy, it's like people grabbing the first Beatles album, because it is the first Beatles album. It's good, but everyone's real favourite is still Abbey Road or the White Album. And for an art analogy, it's the Mona Lisa of the film world; not many people would hang a replica of the Mona Lisa on their wall, but everyone appreciates it.
People look at media of the past and see in such a better light than those of the past. If Citizen Kane didn't turn out to be as important was it was, it would have been forgotten amongst a sea of countless films out there. It's also possible that half the innovative ideas credited to CK were even done beforehand, CK was just the first film to use those techniques and be recognised at the same time. This is just baseless speculating here, but it is not very unlikely seeing as such things happen often.