Considering Jim has said a follow on series with Goodman Gray is in the offing, with Harry featuring as a frenemy, it seems unlikely that magic will go away. The Never Never, things that go bump in the night, vampires, wicked fae, all would seem to feature as prominently as they do in the Dresden Files.
Although Harry and the BAT might cause another change in the magical side effects of mortal magic. Harry might be able to get a cell phone! And drive a reliable car!