Mostly a lack of quality trainers to teach it and also a lack of fighters with the necessary physical attributes to pull off the style.
Most boxers these days are brought up through amatuers and olympics etc on points system I'd guess that has something to do with it It's a real nice style, just watching Frazier and Tyson do it - tis beautyfully :')
hard as hell to use not a very orthodox style either, so not many people knwo the ins and outs of it extremely physically demanding they still teach the style for free at the gym Mike Tyson grew up in: http://www.catskillboxinggym.com/
wouldn't say so kotelnik is a stiff white boy as aggressive as Mike Tyson was his style requires lots of upper body slickness, flava, and swag to do all that head movement and bobbing and weaving
no that's a high guard like clottey and Abraham use. Tyson and Frazier moved the headwith a side to side motion and worked their way inside. Different style. Chisora seems to use mimic Frazier somewhat. Used it to great effect against Helenius. Want to see how well it works against the top tier heavyweights.
because it doesn't really suit the amateur system where the fighters are molded into what they become.
You answered your own question. Body type. Tyson at 5'10 with wide shoulders and thick powerful legs was perfect for that style.
