Why not? Duke is a Nike school.
Blow-out.
Will sign with the company that has best QA/QC.
Because it was a Nike that blew out on him injuring his knee.
https://www.cbsnews.com/news/zion-williamson-injury-duke-basketball-player-out-for-knee-injury-after-blowing-out-shoe-2019-02-21/
Last thing Nike wants is to keep associating their logo with him.
Scroll down the article and you’ll see what happened to Zion’s Nike shoes.