Apple has held onto many proprietary interfaces in the face of much more widely adopted standards, but usually the products have been better off for it. Sure, the one-button mouse is horrendous, but FireWire was better than USB, the Lightning charging port is miles ahead of Micro-USB and other alternatives, and iOS development is not good, but not as bad as Android.
Many things could be better than USB. But U in its name made it the preferred choice. It's like e-mail. Way not perfect, but ubiquitous. Apple not adopting it is clearly anti user in this case.