I believe Adidas told Kanye's Team "Look we aren't 100% sure about this shoe! It's different from anything that we are doing. So do preorders! You sell out 90% then we will manufacture them!" And the rest is a waiting game from a logistical standpoint. I bet Kanye is constantly having to prove himself against their execs. Why else do preorders to guarantee sell? Adidas wants their money upfront. It's like they are making him pay for keys upfront instead of selling him keys outright or fronting him like other collaborators because he has a different clientele!