There's only a license for USB if you want to use the USB trademark, or if you want your own Vendor ID. Pretty much every chip with USB already has paid the money for the Vendor ID because it makes headaches due to collisions, etc, much, much less likely. However, if you need an id, http://pid.codes/ has pids for your use for free. USB over DisplayPort, the company almost certainly has paid for a USB vendor ID, for much the same reason. If you're making a few million chips, the amortized cost of the license becomes less than a penny. Displayport, if you don't want to carry USB, there's no requirement to -- the displayport connectors on my video cards certainly don't carry USB.

Regarding similar protocols, there really isn't anything. One of the lessons from the Bad Old Days is that not having a centralized registry is that you get frustrating conflicts and huge interoperability problems.

With radio spectrum allocation, it's fucked up for a number of reasons, and dissolving it would cause even more problems. Radio astronomy needs clear areas of bandwidth so they can look over the sky and analyze, emergency responders need the same so people can be directed quickly, local broadcasters need it so that people can actually broadcast. Cell phones need them so they can communicate with towers. Radio technology is /complicated/ and at higher frequencies, it only gets moreso. That's why devices need licensing -- if someone screws up the radio hardware/software, it can easily impact more than themselves. Abolishing any sort of spectrum allocation would only lead to a commons that would quickly degrade and send us right back to corded devices.

I just want to point out there is a distinction between allocating spectrum for certain purposes and selling it to private companies. I would never recommend not having a frequency band restricted to emergency communications, though I admit I'm not informed enough about astronomy to know what is optimal there, but I still feel outright saying "you cannot produce radio waves of <these> frequencies, ever" is a very blunt solution.

My larger point is that we have observed in the last twenty years that while signal congestion can be real, we can also now build radios sophisticated enough to deal with it much better than in the past. Things you cannot have interfered with like air traffic control and emergency broadcasts should absolutely be given their own channels, but technology has improved enough that we can certainly stymie their band allocations they are given today without compromising integrity assuming the use of more capable radios.

But even then, I'm not strongly arguing to do any of that - I think it is possible, but I also don't think its particularly necessary - we could simply de-privatize most of the sold off spectrum to private companies to be used for public communications and in the common interest. Think of the Internet bandwidth over air we could get if we had gigahertz of available channels between the 500 to 5000mhz bands.