In NASCAR racing, which went into official existence in 1948, 1972 is identified as the start of the “Modern Era.” The series has yet to become postmodern, but that’s another argument for another digital venue.
The troubadour tradition, that of a musician who sang and played a stringed instrument, goes back at least to the 11th century. One could make the argument that the “Modern Era” for troubadours, or, more to the point of this, singer-songwriters, started in 1962, the year the first Bob Dylan album was released.
When it comes to much music since then, whether it is a Dylan or a Paul Simon or a Jackson Browne, individuals who write and perform their work, or a band, ranging from the Beatles to Wilco and some before and after, it is probably the case that when we hear the music performed, we think of that music, especially vocals, coming from an individual who, in some significant way, has something to do with those lyrics.
To go to the classic case of the Beatles, it was either a “John song” or a “Paul” song, and when it was George or Ringo. . .well, there really weren’t enough of them combined to have a significant effect.
Tweedy is trying to break our hearts.