Really can't blame Nike. Steph was a rising star, but his ankles at the time were very questionable (and that's being nice). They also needed to resign Kevin Durant, who at the time is closing in on eclipsing LeBron James as the best in the world.
Big blow. UA's gamble paid off, literally. But I can't blame Nike for not taking on Steph. Nike had their fair share of shambles on this issue as well, but I think it all boiled down to Steph's then glass ankles.
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Also, I would just like to share a funny story that involves this.
When Manny Pacquiao got dropped by Nike because of his homophobic slurs, a Facebook post went viral, suggesting that "Steph Curry didn't choose Nike because they would not allow Steph to put in a bible verse in his shoes".
This went on, and a lot of people were so gullible that they believed it. I'm pretty sure a lot of Filipinos think that Nike is anti-Christianity because of this bogus claim.