Mayhew stayed with Genesis until his dismissal in July 1970. He was replaced by Phil Collins. In his posthumous tribute to Mayhew, Tony Banks credited him with anticipating, and perhaps influencing, an important aspect of Genesis' later live shows: "John was a bit older than us and had played live in [another band] so had some knowledge of what was expected on stage. I remember him at the first show changing to go on stage; this had never occurred to us, strange since later we became almost better known for Peter's costumes than anything else. For this reason he was a very important factor in those early days on the road, having already been there before." Little was known of Mayhew's whereabouts following his departure from Genesis. There was speculation that he was deceased or missing. In 1982, he moved to Australia, where he found work as a carpenter. In 1989, he briefly returned to England to visit his ailing mother. In 2006, he attended a Genesis convention in London (along with Anthony Phillips and Steve Hackett), and played drums for tribute band ReGenesis's performance of "The Knife". On 26 March 2009, Mayhew died of a heart condition in Glasgow, Scotland on the eve of his 62nd birthday. He had been working as a carpenter for a furniture company at the time of his death. He was survived by his brother.