Complex sentence: By the 1970s, sales of Kaempfert's music had dropped off somewhat, but he continued to record (his version of the "Theme from Shaft" was admired by Isaac Hayes himself) and remained popular with audiences.
Split into simpler sentences: By the 1970s, sales of Kaempfert's music had dropped off somewhat, but he continued to record. His version of the "Theme from Shaft" was admired by composer Isaac Hayes and remained popular with audiences.