In the Rodgers and Hammerstein generation, popular hits came out of shows and movies.

Sondheim is contrasting mid‑20th‑century Broadway/Hollywood’s relationship to the pop charts with the later separation of “show tunes” from mainstream hit-making. In the Rodgers and Hammerstein era, musical theatre and film musicals functioned as a primary engine of popular song: numbers written for narrative performance (“Some Enchanted Evening,” “Oh, What a Beautiful Mornin’”) routinely became widely recorded standards and radio hits. The remark implies a shift in the music industry and audience taste—toward rock, singer‑songwriters, and record-driven pop—so that theatre songs increasingly circulate within theatre culture rather than dominating general popular music. It also underscores Sondheim’s awareness of changing conditions for songwriters and the declining likelihood that Broadway songs would become mass-market hits.