Comment by sroussey

A voice on the radio sounded better with vibrato, so that’s what they did before even recordings were made. Same when violins played.

These versions were for radio only and thought of as cheap when done in person.

Later this was recorded, and being the only versions recorded, later generations thought that this is how the masters of the time did things, when really they would be booed off stage (so to speak).

It’s a bit of family history that passed this info on due to being multiple generations of playing the violin.