I always wondered why there is so little magic in the stories universe?
Why do white walkers have acceess to magic but no one else?
Why do white walkers have acceess to magic but no one else?
That said, it also does make possible some "cheap shot" plot devices like a certain important someone getting assassinated by a certain priestess in an unlikely way. (Details elided to avoid spoilers).
For most people in that world, magic has never existed outside of legends, and much of the knowledge on how to use it is gone or at least not available to most people (probably only in historical records at the Citadel).
The TV adaptation also downplays the magic more, either out of budgetary reasons or to keep it more accessible to a general audience.
George Martin chose to make the story about people and the struggle for power and ideals and everything else that is human. And even with magic being barely a presence, it still is a force able to radically influence the game - but not much more than money, or armies, or human ability, which are still powerful enough to be relevant.
I think if magic was more widely available, it would either have needed to be trivial, not powerful magic, or these other resources would have suffered.