Every time any episode of THE NEW TWILIGHT ZONE or the second and third seasons of BEAUTY AND THE BEAST aired anywhere in the world or sold a DVD he got a chunk of cash, and a lot more than what he gets per individual book sold. FEVRE DREAM had also been optioned as a movie several times, the film and TV rights to WILD CARDS had also been sold a couple of times and so on.

WILD CARDS was also a massive-selling series in the 1980s and a bit of phenomenon, hitting the bestseller lists and so on. It was the success of that series that led to the flurry of interest by several different publishers when AGoT was being shopped around.

ASoIaF is really not the massive mega-selling giga-series people seem to think it is. It's sold impressively, certainly, but even on a per-book basis he's a long, long way behind the likes of Jordan and Goodkind, although he's now overtaken the likes of Feist and Brooks (on a per-book basis, not overall). To put it another way, the entirety of ASoIaF has sold less than THE EYE OF THE WORLD by itself (and for comparison purposes the entirety of the MALAZAN series has sold less than A GAME OF THRONES by itself).