Free time is one factor but other factors include declining health (people that have lived the touring lifestyle understand how harsh it can be physically) and

Free time is one factor but other factors include declining health (people that have lived the touring lifestyle understand how harsh it can be physically) and dying. Add in children and the complications of having a 10 year old listen to Cannibal Corpse with you as a hypothetical situation. One other factor not commonly mentioned is that many people ossify and have difficulty expending the mental energy to seek out new music. I personally don't do that anymore but I certainly did for a while when I was much more stressed out with work. Additionally, some genres themselves seem to get into a rut and tap out (let's not forget the "punk's not dead" attempts at denying reality, for instancee)