Kyi May Kaung - Is it Sci Fi without the Science

I am thinking of Dune, or A Canticle for St. Leibowitz, or George R. R. Martin's work, where technology is changed to magic or all technology is almost all lost. Why isn't sci fi fantasy? Why should we worry so much about labels and categories. What is the bottom line.

George R R Martin - fantasy and sci fi writer

http://en.wikipedia.org/wiki/George_R._R._Martin

31 stunning sci fi illustrations -

http://www.designzzz.com/stunning-futurisitc-scifi-illustrations/