Once people either had to go listen to a musician or make music themselves. Some would learn an instrument, but many would sing. In the US, everyone from college fraternities to Temperance groups would have their own songbooks in the 19th c. Traveling teachers , like William Billings in New England and B.F. White in the south, would set up singing schools to teach people how to read hymns that could then be sung in church. In England, Flora Thompson noted how the farm laborers would gather in a pub, each would have one beer and sing one song, then return home. And of course you can trace popular singing back quite far. Ballads would be composed on topical themes and sheets of them sold in markets in 17th c. Most of the medieval music that survives is sacred vocal not secular instrumental.

The advent of good audio recording and mass production of recorded music made it possible to divorce the performer from the performance. Fiddlin' John Carson recorded Old Joe Clark, in the 1920's, and it sold over a million records . If Carson had had to play that 3 minute tune that many times himself, it would have taken more than a hundred years, but now the tune could play without him. Music could be a commodity. That accessibility of well-performed music by the distribution of low-cost phonograph records naturally eroded participatory music. There was further erosion when better sounding "hi-fi" electronic audio equipment appeared, bringing even grand operas into the home. And then studio techniques such as multi-tracking, and studio effects such as reverb and compression, made it possible to create and hear audio recordings that could not be matched by a live performance ( most people will date this, the studio album, to the Beatle's Sgt Pepper's record) . That has created quite unreal audience expectations for audio quality and effects in live concerts, as well, tempting performers even to lip-sync to their own recordings instead of disappoint with the less-impactful live sound . ( You may not realize you have those expectations, but you likely do- even the recent series Glee showed choirs apparently performing acapella, but with the actual sound obviously heavily processed- compressed, given reverb, parts individually pre-recorded and then mixed to sound amazing. It is the New Normal)

Seeger was one of many folk musicians who knowingly tried to go against that trend. The folk revival in the US that he helped lead in the 1950's was centered around singing in concerts or in "hootenanies" / sessions, and Seeger himself would always have his audiences sing with him, as did most other folkies, from Jean Ritchie to Bob Beers. To that end, some of the most popular choices for folk concerts were songs that had a good chorus, like Malvina Reynolds' Little Boxes, or the traditional The Wild Mountain Thyme. In England, people like the Waterson family tried to bring back the traditional songs and also the tradition of pub singing- with some success. But like people baking their own bread and making their own clothes, participatory singing has fought a battle with commodification. And, as you see people jogging or commuting with headphones in place, thousands of recorded songs available on their devices , it seems to be losing.