It's true that accompanied singing was the norm during the revival. When my dad was a lad they sang unaccompanied most of the time because few working class people carried instruments around with them. Accompanied singing took place in homes and pubs when there was a pianist there, otherwise it was unaccompanied.
Bob Copper remembers being stood on the table of a local hostelry and singing while his dad got free drinks because folks liked the entertainment. Knowing Bob, he probably got a drink or two even though he was as young as eight at the time.

Singing unaccompanied is still the norm round here. It is easier to be expressive when you are not restricted by the rhythm of an instrument like a guitar. A few clever clogs can sing and play squeezeboxes at the same time. Most of us can't even talk when playing, or we lose the tune completely.