> If you mandate that all electronic devices must have USB-C cables, how can anyone invent something better than a USB-C cable?

That already happened with Micro USB. The EU initially mandated that manufacturers agree on a standard socket, because the absolute zoo of charging ports back then was counter-productive and only generated e-waste. Ultimately they agreed to use Micro USB, but obviously that's not what's used today.

These regulations are not just dumped on the manufacturers - there's a period of consultation and a grace period to implement them. If something actually better came up, you'd eventually see it mandated.