Dammit JD you've just beaten me to a point I was going to make.
In a fair few Fantasy novels especially Mr Moorcocks we see the use of technology far enough advanced to be considered magic.
As to it being necessary, I do wonder if a novel is actually fantasy unless it actually involves a little "higher power" divine or magical.
While I like the Gormenghast books, are they fantasy? Depends on what we percieve as fantasy I suppose. Isnt all Sci-Fi just fantastic fiction really?