I was a buyer for a chain of 3 shops before the e-bike craze took off, but still have some friends working in local shops. No one wants to work on other brands’ stuff. There are too many people coming in with problems they don’t understand, just to have stuff like controller or motor failures and the shop gets stuck in the middle.

Most shops are hobby businesses that barely break even in the best case scenario. The only part of a shop that keeps the doors open is service. These kinds of major time sucks are what will put a shop under very quickly. The lack of standardization is criminal exploitation that hurts everyone. Proprietary means theft of ownership in every instance. You never own proprietary products; they own you.