That's a good question. There can be no doubt that Tony was a better fighter in his early 20's than in his late 20's. Mileage was the culprit. By his late teens he already had some serious rounds under his belt, and then he proceeded to take his talent off-road. The frenetic manner in which he hopped between weight classes would be considered suicide today. In doing so he carved out an awesome career, but it gradually weathered his engine. Canzoneri was very probably a lesser fighter after that rivalry with Barney Ross, but some newspapers were of the opinion that (before the first fight) Tony was "a bit shop worn now after eight years of warfare." To see him tame a young Lou Ambers further down the road must have been magical viewing - an old school Morales/Pacquiao I, if you will.
Tony Canzoneri was so beloved as a fighter who went 174 bouts against the best featherweights and lightweights without EVER being ko'd, that in his last bout in 1939 the old creaky Canzoneri ,was kod by the new sensational left-hooker Al Bummy Davis, who was booed after he kod Canzy,and Davis became a pariah to thousands of boxing fans... Canzoneri became an owner of a bar near old MSG on 8th Ave,and then part of a comedy team with Joey Adams. Sadly Canzoneri died alone in his hotel room in 1959...One of the truly great modern lightweight fighters ever...