Complex sentence: It was in the 1970s when fans and detractors began referring to Wilson as a burned-out acid casualty, and he would not attract the level of press attention he achieved in the 1960s until a new marketing campaign was devised in 1976.
Split into simpler sentences: It was in the 1970s when fans and detractors began speaking of Wilson as a burned-out acid casualty. He would not attract the level of press attention he achieved in the 1960s until a new marketing campaign was devised in 1976.