You're mixing up "interfaces" that should be standardized, and products on either side of the "interface" that must not be standardized!Consumers and businesses should generally be free to adopt the standards they believe best meet their needs—provided they don’t violate the rights of others in doing so.
They should be free to offer competing alternatives to challenge the status quo.
What if there had been a standard requiring all phones to have physical keyboards? You could justify that with the same “common good” argument used here.
Keyboards and phones must use the same interface (bluetooth) to exchange data. Companies must use the same currencies to exchange funds. People need do talk the same language to exchange information.
It's actually the standardization of the interface (here: USB-C) that enables a free choice on either side (i.e. free choice of phones on side A and free choice of charger, display, keyboard, storage system, game controller, earphones on side B).
And the standardization of the INTERFACE enables innovators to invest in new product development (phones or periphery), as they can trust that they can actually sell their product to a large number of costumers (without having to fear that their device won't be compatible by then).