Complex sentence: Since the time of big band radio shows there has been an established relationship between musicians and commercialisation, and it was not until the punk subculture in the 1970s that the notion that musicians should be completely independent of commercial influences began to increase in popularity.
Split into simpler sentences: Since the time of big band radio shows there has been an established relationship between musicians and commercialisation. It was not until the punk subculture in the 1970s that the notion that musicians should be completely independent of commercial influences began to increase in popularity.