Final answer:
The originator of the quote regarding free jazz as the most significant innovation in jazz since the mid-forties is not provided, but the evolution of jazz music, including free jazz's emergence, represents a significant chapter in the genre's history.
Step-by-step explanation:
The individual credited with stating that free jazz is "the only really new thing in jazz since the innovations in the mid-forties of Dizzy Gillespie, Charlie Parker, and those of Thelonius Monk" does not seem to be cited in the provided information.
However, the history of jazz music indicates significant evolutions over the decades, with groundbreaking contributions by various artists.
Free jazz, which emerged in the 1950s and 1960s, is considered by many critics and jazz enthusiasts to be a major development in the genre, radically departing from the conventional structures and forms that defined earlier styles.
Jazz itself originated from African American communities and experienced widespread popularity in the 1920s, known as the Jazz Age, with the innovation reflective of diverse musical traditions like blues and ragtime.
The description of free jazz as being distinctly innovative suggests that it captured the spirit of autonomy and creativity that was central to the art form's evolution, extending the boundaries of jazz music even further following the bebop era.