On Duran/Armstrong and the abuse their bodies went through... There aren't a massive amount of fights and rounds separating the two. Certainly a difference but not a massive gap. Duran was certainly active a hell of a lot longer, abused and took a toll on his body like Armstrong never did, probably had far more rounds of sparring then Armstrong ever did hence more abuse in that sense, and moved all the way up to LHW. I think Duran could have definitely had as many fights as Armstrong and not tarnished his record. 60 more fights squeezed into Duran's early and middle years wouldn't have killed him if he'd quit the booze, drugs and weight gaining.
One of, if not, the greatest to ever do it. Amazing, amazing fighter. And I do agree, he could be the greatest fighter who EVER LIVED.