It's a "decentralized" world wide web then.
The internet is already decentralized and since you need the internet for Urbit to work let's stop calling it "the internet" anything.
You'll have to take that up with the public at large. We use "internet" to refer to the world wide web. Try to sell someone a computer that has "the internet", but won't do tcp/IP, you'll get punched.
As for the infrastructure, that's a rather more esoteric concern. It needs a distinguishing term.
As for the infrastructure, that's a rather more esoteric concern. It needs a distinguishing term.