I think that is debatable. Mind you, I say this as someone who preferred Wheel of Time to Game of Thrones, for a variety of reasons. But I think in terms of cultural impact, at least as of right now, GoT--via the tv series--inhabited a space in the public mind that WoT has not (yet) touched.
Now within fantasy literature is a different matter, although I still think isn't a clear-cut case.
As for your last sentence, I think that is a bit dubious, because then we can say that Tolkien trumps all, or even, Shakespeare or Homer or Gilgamesh trumps all. I think it is more meaningful to consider every book or story or author as a starting point of a "sphere of influence," and then specify a context.
So I think within the context of fantasy literature, it is debatable. Within the context of Western culture, GoT has been more impactful (so far).
In terms of cosmic history, neither is more or less impactful unless, of course, WoT inspires some mad scientist to create balefire, and then we're in trouble.