It is not realistic, maybe ... but art doesn't have to be realistic. Romeo and Juliet is not realistic, but it is true... it shows the essence of falling in love.
Most books about Stanley Kubrick were written by people who never met him and gathered information from articles written by others who didn't know him either.
It is amazing that 2001: A Space Odyssey has not aged at all, except for a few minor technical gadgets. The main reason is, of course, the philosophical or spiritual element in this story. We know as little today about the secrets of Creation and evolution as we knew before, and it is not likely that we'll ever know much more. We'll have to be satisfied, as Kubrick was, respectfully admiring the potential for evolution within the mystery of the universe's creation.
