Yup, very good article, though it is definitely written from an American point of view. I'm sure they could have squeezed in a few Brits or europeans into that list.
However, when it comes to being the greatest, then surely one of the factors that should be considered as a boxer is knowing when to retire at the right time in one's career. If you look at the two fighters who have fought in the past 12 months on that list, they are both old, arguably washed up and would have been much better off throwing in the towel when they were near their peak, rather than sullying their legacies with pointless wins and defeats to fighters they would have whupped when they were at their best.