There is a point about SF (not) being "obsolete"
Neil Armstrong?s first footsteps on the Moon in 1969 made obsolete a whole library of science fictional dreams of lunar exploration, from H. G. Wells (The First Men in the Moon, 1901) to Tintin (Explorers on the Moon, 1954). But nobody would suggest expunging Wells?s great book from the canon for such a literal reason; the fiction is what counts, not the science.
This resonates with a few things I've been thinking about recently. Firstly there's a line in The Complete Idiot's Guide To Publishing Science Fiction which says something similar, I've been re-reading that book as I am nearing the end of another draft of my second novel and need some perspective. It also ties in nicely with the Studies in Narrative: Science Fiction and Fantasy lectures that I have been listening to, I've particularly enjoyed hearing about and thinking about some SF classics. And one thing crops up again and again, if it's a great story then people will read it.