ed preceded TCP (first ed manual I could find is dated 1971; the first TCP research paper was by Cerf and Kahn in 1974). When ed was used, it would be common t

ed preceded TCP (first ed manual I could find is dated 1971; the first TCP research paper was by Cerf and Kahn in 1974). When ed was used, it would be common to interact with the computer on a teletype, not even on a crt monitor. So a response meant printing characters on paper. sed was and is more about programmatic editing (i.e., editing a stream as it was generated, using a script for commands), or editing of large files that would overwhelm system memory, not about some kind of remote usage the way you're describing.