How long have they been doing music for....wow. I really wish I could answer that. If only there were some sort of vast digital database that could be asked any question, and give a reply in mere seconds.
Shoot man, since the late 70’s. At least for Bob, he was born in 1957 so he’s been at it for a while. GBV didn’t really get popular until the mid 90’s by the time he was in his late 30’s