Slowly? It seems to be returning rapidly. Dragons to the south. Zombies to the north. White walkers ripping peoples heads off in the snow last season. They say Rob can turn into a wolf or rides his wolf into battle. Wildfire under the capitol city. Oh and shadow ghost demons carrying out assassinations. We've even got what seem to be pretty powerful warlocks down in the desert.
The magic is downplayed, but it definitely exists. Beyond just a science that they don't understand. Like real swords and sorcery genre magic.
Tiny dragons hardly anyone has heard of yet, let alone seen. So small they can barely singe a mouthful of steak to feed themselves.
The zombies in the north aren't at zompocalypse numbers either. Again, a few people know about them but we're in double figures there, no more.
The same with the White Walkers and there's been a grand total of one shadow-demon attack so far. Only a few people know what happened to Renley, no-one else even suspects magic.
Rob isn't really the North's Teenwolf either.
The point has been made several times that magic is something from the past. Tyrion mocked it, Maester Luwin dismisses it, Cersei ignores warnings and with good reason.
Westeros (and beyond) have plenty of superstitions but for centuries that's all they've been.
And that's important to the plot. If magic was still real in this world, rare and precious but available, then it would be used and feared in a way that it simply isn't
by the main characters. Most Maesters don't study spells, the Warlocks are assumed to be faking their "tricks" and The Wall is undermanned and under-maintained.
The slow, scattered return of magic is going to have a bigger effect because its slow and scattered. For now.
Winter is coming.