 Mainer retired from General Motors in 1973 . Mainer has been credited with bridging the gap between old @-@ time mountain music and Bluegrass and musicians such as Bill Monroe , Ralph Stanley and Doc Watson have all cited Mainer as a source of influence . He has also been called the " Grandfather of Bluegrass . " His influence was not limited to the United States . Pete Smith , of the British newspaper The Advertiser , in a report for Mainer 's 100th birthday , cited Mainer as " one of the most influential figures in the development of modern bluegrass , " noting his picking style and his efforts in bringing bluegrass closer to the mainstream . In addition , Smith also credits him for making the banjo , an instrument previously described as " satanic , " acceptable for spiritually @-@ themed music . Mainer continued to live with his wife in Flint , where he celebrated his centenary in 2007 and performed at a concert for his 101st birthday in 2008 . Mainer died of congestive heart failure on September 12 , 2011 . He was 104 . 
