Presently, I'm reading an anthology: The Best Tales from Astounding Science-Fiction 1938/1945. The two books I read just before were anthologies of old S.F. novelettes, too.
Let's see the positive side of things: novelettes are better than novels... as long as they're annoying or uninteresting, otherwise, it means they're intesersting ;o) It's a way to give an author a chance to please me without bothering me for a too long while ;o)
Do you know that many Hollywood's S.F. bestsellers are based on these old authors' novels or novelettes? Do you need examples? Check for Starship Troopers (Heinlein), Planet of the Apes (Boulle), 2001 a space odyssey (Clarke), I am a legend (Matheson).
By the way, I've been lucky enough to watch "La Jetée", the Chris Marker's short movie the famous "12 Monkeys" is based on. The whole short film is as strange as the full-length's scenes in the future.