Oh, Hello RDF.[0] (Granted, in RDF everything is a URI but that's a minor detail here.)
At one point in my life I spent two years trying to work with RDF based data store modeling. Shoehorning everything into the subject-predicate-object worldview is probably beautiful from a purely mathematical point of view, but utter insanity in the real world.
Now, s-p-o model does open up a world of very interesting graph-theory approaches, especially if you're trying to build an inference engine. But at least in my experience it's not a realistic way to build general applications.
And if you thought XML as a data interface format was bad enough...
0: https://en.wikipedia.org/wiki/Resource_Description_Framework
Do you mean "everything not on my machine is a URL"? We're getting somewhat close to that already.
Or do you mean "everything on my machine is a URL"? Then I don't see how it's different from "everything is a file with a full path", except that someone else is now responsible for the security mechanism.
"Everything is a URL" would give you a unified view of on-machine and off-machine resources...
Games get to do this because they don't care about interoperability. The packfile is intended to be a closed environment accessible only to the game code itself, with no need for anything else to care about it.
This could be interpreted as a particular case of "can't trust the apps" - a game has no need or desire to trust anything else.
Not sure what you're accomplishing exactly. Something would have to serve said url and you are moving your security problems into it. Mostly you can accomplish many of the same things with file security, with some difficulty.
Given the same title, I would write a rather different article. So many of our traditional filesystem problems center around concurrency: what kind of read-after-write or durability semantics are guaranteed. A lot of effort goes into this, which is necessary for databases to work on top of a general-purpose filesystem on top of a disintermediated storage system that may be a disk or SSD with a variety of block sizes. But for most operations it's unnecessary overhead.
Many games ship with a "packfile", which is a pseudo-filesystem that appears as a giant blob to the OS. Usually it's faster to seek individual small items out of the blob than if they were separate files.
Further to that is the security problem; we've moved from "apps are all trusted, but you need to watch the files closely between multiple users" to "there's only one user, but you can't trust the apps".
Note how the cloud has avoided both of these by moving storage to three different areas with different semantics. Apps can speak to "blob storage" (S3) which has a transactionality/security granularity of one blob. Or they can speak to a database (which has intelligence of its own), or separate raw block storage if neither of those suits.
What if we moved from "everything is a file" to "everything is a URL"? Possibly adding a system-default packfile mechanism. So an app would be allowed access to everything that it ships with, but nothing outside except what it could request as URLs with various sorts of security mechanism.