You've got to compare apples with apples. Michael Phelps wouldn't have beaten that many records if the US program and his fellow US swimmers weren't that good. If you're the best swimmer in high school and the other guys suck, you won't need to add the extra hour of training here and there to remain the best and slowly become a much better swimmer. The problem with boxing (not a huge one, because we get great fights nowadays anyway) is really at the bottom. Boxing gyms in the US aren't as popular as they was. Look at the great Philly scene, it's all but disappeared ! Boxers got to travel to places like the Kronk to get a great environment.
wow the idea of Kermit Cintron lasting five rounds with a tenaciously tough Robinson is insane - Kermit Cintron is fragile and weak mentally. This is something that won't change just because he has the modern nutrition of McDonald's and there are some weights in his gym. People overestimate modern athletes. Hopkins is practically geriatric and still schooling guys. Boxing is not like other sports in this regard. You need the right combination of tangibles and intangibles. Erik Morales does not really have advanced training methods: a tough guy who grew up in a boxing gym who probably eats a lot of quesidillas and sometimes drinks Tequila. He could have been in his prime in the 70s and would be the same guy, a flat footed combination puncher with a great chin.
I agree that athletes progress, but to say that Ali couldn't contend with Lewis or the Klitchkos is kind of ridiculous. Ali had one of the greatest chins ever. Having a great chin is something that transcends eras. Neither of the Klitchkos nor Lewis has a good chin at all. Also Ali was a very athletic heavyweight, even by today's standards. This is possibly the worst example you could've used.
Look at film. Look at the one art of Heavyweights that has been lost over time - Footwork. Ali's fluidity, movement, and overall skill and grace makes me believe he would be just terribly hard to deal with by the likes of today's HWs.
It's more spread around the world than before, without a doubt, and it is pretty clear that european boxing has taken a huge step forward the last 20 years. However, I feel that the fact that all the talent is less concentrated right now could be a part of the reason why we see (in my opinion) less skilled boxers nowadays. A guy like Mayweather looks extraterrestrial in this era, as I can't think of anyone who can dodge, block and counter punches like he does. Put him in the 30's, 40's or 50's and he wouldn't look as out of place next to the likes of Sugar Ray Robinson, Willie Pep, Holman Williams, Ezzard Charles. In the 80's you had multi-dimensional guys like Sugar Ray Leonard, Roberto Duran, Tommy Hearns, Marvelous Marvin Hagler. I'm not a guy looking at the past through pink glasses. I love nowadays boxing and I see good fights every months. However, I can't manage to name as many skilled fighter that have boxed in the last decade. Guys like Mayweather, Marquez, Pacquiao, the Klitschkos, Hopkins, etc would do well in any era. However, I would certainly not show tapes of Pacquiao or the Klitschkos if I was a trainer. I would show them tapes of Joe Louis, Ray Robinson, Roberto Duran, Ezzard Charles, Charley Burley, Willie Pep, Julio Cesar Chavez and Floyd Mayweather. Those fighters perfected their art so well I could nearly not show you a hole in their game. They spend hours after hours in the gym, looking at better fighters than themselves to learn how to box. Boxers train as hard nowadays, I have no doubt about it, but I'm not sure if they look that much at boxers who are/were better than themselves. You can't look at Roy Jones Jr. if you don't have his reflex. You can't look at Pacquiao if you don't have his rare mix of speed and power. Maybe the problem is that too many wants to be the next Ali, Jones Jr or the next Pac, while they would do better trying to look at Marquez. We've rarely seen that special kind of technical fighters in the past 20 years. I can name Mayweather, Marquez, Toney, Hopkins, but they are getting old.
Imagine if 5ft 9" middleweight Marvin Hagler was 40 years old, was well past his best, had ballooned up to 240lbs and you then transported him him into todays heavyweight division. Now if I suggested that such a version of Hagler would be competative I would be laughed at by certain people on here. But guess what? That is exactly what happened with James Toney. And why? Because unlike many of todays fighters Toney actually has skills and well crafted boxing fundamentals combined with the intangible that is a granite chin.
Lewis couldnt Ko Tua, Akinwande and that Macrovic bum, but hes going to hammer Muhammad Ali? Bowe went life and death with Holyfield 3 times, despite his size. Vitali quit against Chris Byrd and struggled to KO Chisora, but hes going to smash Joe Frazier? The only decent fighter Vitali ended in the first round was Solis...and that was because Solis was so fat he popped his knee. So much for modern nutrients i guess. But no, Vitali is going to do Lois in 1 round, when it took him 8 to take out Danny Williams Wlad couldnt even KO Haye, but hes going to KO Dempsey? Larry Holmes, George Foreman, Mike Tyson, Evander Holyfield, Lennox Lewis, Vitali and Wladmir all have at one time or another stated, Ali is the Greatest Of all Time. Welcome to my Ignore List