Complex sentence: "Progressive rock" eventually morphed into a set of conventions to be repeated and imitated, which led to "post-progressive" rock music, while the "progressive" label would also be applied to several sectors of post- 1970s electronic music.
Split into simpler sentences: Progressive rock eventually morphed into a set of conventions to be repeated and imitated, which led to "post-progressive"rock music. The "progressive" label would also be applied to several sectors of post- 1970s electronic music.