@solderpunk In a sense this is already possible its just that no one wrote the tools to connect it all. The whole idea of a URI is it can reference anything on your system, a file, a website a piece of hardware, anything. So in theorry you could copy and paste anything (the URI would be the thing in the clipboard) and wherever you paste it to would have access to the resource...
The issue is there are very few apps that will handle the URI once you pasted it in a way that is inclusive to a large array of resources.
So the limitation isnt in the copy-paste mechanism so much as it is in the apps that utilize copy-paste.