On the surface, Deep Purple had a great year in 1973. That was, after all, when "Smoke on the Water" peaked at No. 4 on the Billboard Hot 100, also giving them their most recognizable hit. However, infighting was beginning to tear the band apart, as Ritchie Blackmore fired bassist Roger Glover, effectively ending their Mark II lineup, as noted by Ultimate Classic Rock. Around the same time, Ian Gillan also left the group, submitting a resignation letter to his bandmates while they toured behind their album "Who Do We Think We Are."
In 2020, Gillan spoke to Classic Rock Magazine (via Louder) and talked about why he opted to leave Deep Purple in 1973, stressing that the "deep" in the group's name is the "opposite of shallow" and mentioning that he quit because a "hint of commercialism crept into the band." He also suggested that it was Blackmore who was behind Deep Purple's switch to a more commercial sound. "He had an ear for the more popular stuff," Gillan explained. "And it was very successful. But I thought it couldn't survive, because it was planting itself in a fashion, and fashions come and fashions go. Once you're out of fashion, you're out of fashion."
If Gillan and Blackmore were indeed feuding about Deep Purple's creative direction back in '73, it was just one of many conflicts they were facing. And it wasn't as pronounced as the bigger issues they had with each other in the coming decades.
