Why is "2001: A Space Odyssey" considered such a good movie?

[Bohandas]

Why is "2001: A Space Odyssey" considered such a good movie?

It falls short in so many ways. It moves at a tedious pace. All the sets and props are drab and dull to match. And most importantly of all, it doesn't make a bit of sense; the plot starts out incomplete and by the end of the film is abandoned altogether in favor of what appears to be the director's hamfisted attempt to reproduce an LSD trip on film (apparently this is supposed to represent the protagonist being transported to an alien world and having his brain uploaded, but I only know that because I read the book. There's no way that you could get this just from watching the film).

What gives!?