Should content always dictate form?

As Sondheim insightfully noted, if "content dictates form," the question arises: what do you do with songs when you embark on a total rewrite? While one might consider keeping them on the sidelines to be tapped into when a new place arises, this approach seems to challenge Sondheim's philosophy.

Have you ever found yourself in a situation where you've written a song and then attempted to retrofit it into a musical scene? I wonder if the great standards from twentieth-century musicals, such as those by composers like the Gershwins, Berlin, Porter, adhered strictly to Sondheim's rule.

And Jukebox musicals start with songs as puzzle pieces that weave themselves into the fabric of the story. I guess they get a pass since the songs are already well known.

Would love to hear your thoughts on this approach and whether you believe in adapting your songs to the evolving narrative of a musical.