WIRED published a (relatively positive!) article last fall entitled "Google Wants to Kill the URL": https://www.wired.com/story/google-wants-to-kill-the-url/ I'm interpreting the title as a reference to that.

And the relevance is that AMP shows its own fake-URL bar, and Google could choose to "kill the URL" by trusting https://www.google.com/amp/ with not-URL overrides. (But, they could do that presently and trust themselves with URL overrides.)