We don't need agreement for this. In the past, hardware was limited, and you could only really implement one (maybe two) network stacks before things got silly. Nowadays, a software-defined radio can speak ten thousand protocols, for a lower cost than saving a cat video to your hard drive.

We only need that the standards are open, and described clearly enough for a schoolchild to implement, and that we are not prevented from adding additional protocol support to systems we acquire.

Hardware protocols are a bit different, but I actually dislike the USB-C standardisation. We already had better de-facto standards (e.g. small, "fixed-function" devices like feature phones and e-readers all use Micro USB-B for charging). Our problems were mainly "this laptop barrel charger is incompatible with this other laptop barrel charger", and proprietary Apple connectors.

The most important hardware protocol is power supply, which we can fix by requiring well-documented, user-accessible contacts that, when sufficiently-clean power is applied to them, will power the device. These could be contacts on the motherboard (for something designed to be opened up), or something like Apple's Smart Connector (without the pointless "I'll refuse to charge until you handshake!" restriction).

Requiring open, well-documented protocols which aren't unnecessarily-complicated is imo more important than requiring standard protocols.