This is such a made-up idea.

The various treaties about freedom of passage exist precisely because, before the last 200 years, everyone did whatever they wanted with straits and other natural chokepoints, including closing them at will. Freedom of navigation is not an obviously natural right nor one universally accepted, before colonial powers effectively invented it and enforced it with guns. If somebody shows up with bigger guns, it might well disappear again.

Also, I wish the expression "close but no cigar" could be banned on the internet. Unless you're a professor of international relations at a renowned university, you simply don't get to gatekeep what reality is - particularly when making up arbitrary principles like these.

> colonial powers effectively invented it

“In both Roman law and Islamic law, notions of a commonality of the seas were firmly established” (Id.). (It’s also weird to describe a custom of commons as colonial. European colonialism was about the opposite, turning historic commons into private rights.)

As a normative concept, you’re right, it’s new. But the notion that a great power would protect sea access for a variety of groups is old. More as a practical matter, granted—it’s hard to project enough power onto an ocean to control it.