I think there's a danger of that, at least if countermeasures are not easily available for normal shipping.

Even 1-on-1 rather than 1-v-everyone, there's too many players (not all of them nations) with too many conflicting goals and interests. If Cuba tried to do it, could they credibly threaten to sink all sea-based trade involving the USA? If not Cuba, who would be the smallest nation that could?

And the same applies to Taiwan and China, in both directions, either of which would be fairly dramatic on the world stage, even though China also has land options. Or North Korea putting up an effective anti-shipping blockade against Japan.

> But to a level where military escorts can feel safe.

Are there enough military ships to do the escorting?