Could “sloop” have survived after 1945?

The closing thought experiment asks what might have happened if the Royal Navy and comparable services had retained 'sloop' instead of adopting 'frigate' as the familiar label. The question separates institutional language from the physical evolution of escort warships. Modern escorts might still have inherited the sloop name, or the term could have developed a different postwar meaning as frigate did. The Black Swan emerges as a mature escort design in its own right, independent of its later place in frigate development.