Mayweather earned his stripes. Simple as that.
He was hard-working coming up as "Pretty Boy" Floyd and took it easier with the toll on his body and hands as he got older. He had the best work ethic and dedication to the sport imo. It's wise for him to work smarter to save him from further injuries as he gotten older.
at first it was hard work, then that platitude was replaced with work smarter, not harder which implies to me pick easier opponents and get the same rewards