Adidas has completely reinvented themselves in the perception of the millenials and Kanye was a big part of that. NT would never admit that though because a lot of people on here are vehemently anti-Kanye to offset the blind slurpage of him. They find some sort of weird pride in being anti-trendy or not letting celebs influence what they do or wear at all.
However, they also came with new, innovative and good product. They couldn't just throw a pair of Kobe 2's on Kanye and expect him to rejuvenate the brand, they came with heat on their part.
It was a combo of good product, good marketing and Kanye increasing the visibility of that new Adidas. Even if you don't necessarily buy a a pair of sneakers because Kanye wore them, he is a factor in your purchase if you see Ultra Boosts on an IG page or post that wasn't posting the shoe or even covering Adidas period before Ye started ******* with them.