Only because they didn't know how to ask the vendor to do it for them.

I guarantee this vendor would be delighted to make them to spec at a 1ku volume, max. Rewinding isn't even a meaningful SKU distinction or line retool, it's a configuration parameter.

At 12 motors per product, it's easy to hit MOQ.

There are inventor programs that'll literally ship you to Shenzhen to build connections to manufacturing sites and even provide you with a liaison, etc. I only know this because I was once in a program that did exactly this.

Reminder that this was a student project.