He may yet have to revise that assessment, at least in the cases of manager Brendan Ingle and promotor Frank Warren, whose combined talents have steered the precocious "Prince" Naseem Hamed to the verge of a world championship and a million-pound contract before the 21-year-old has even challenged for a British title.
The latest and perhaps final stage of Hamed's apprenticeship takes place on Saturday night at the Albert Hall when the Sheffield youngster meets Juan Polo Perez, a former IBF super-flyweight (8st 3lb) champion from Colombia in a 10-rounder which should tell us much about Hamed's long- term prospects.
The choice of venue, too, offers its own comment on the status and importance Hamed has already assumed in the British boxing industry. The Kensington arena was once "headquarters" for the sport, particularly in the Sixties and Seventies when Duff and his associates - who enjoyed a virtual monopoly on big-time boxing until Warren's emergence in the early Eighties - promoted monthly shows there. In recent years, though, it has been sadly under- used: in fact this will be Warren's first promotion there for seven years, and it has taken a crowd-puller of Hamed's magnitude to persuade him.
In a sense this promotion is a symbolic landmark in Warren's own roller- coaster career. There is a certain sour-and-sweet symmetry about the reflection that what was almost his last show here featured the final ring appearance of Terry Marsh.
The former IBF light-welterweight champion was later acquitted of Warren's attempted murder in the shooting which precipitated the promoter's financial problems, so Warren will relish this triumphal return there with the hottest prospect in the business under his wing.
His fortunes are inextricably linked to Hamed's since the undefeated Yorkshireman was, with Mike Tyson, the pivotal figure in the multi-million deal with Sky Sports which secured the futures of Warren and his ever- expanding stable of boxers. That mega-deal has made Warren the single most powerful man in British boxing, a fact which the fighters themselves are recognising by the speed with which they are defecting to his camp.
Alfred Kotey, the superb WBO bantamweight champion from Ghana, last week jumped ship from the KOPRO organisation in which Roger Levitt is involved and was joined by Neville Brown, the British middleweight champion who was formerly under Duff's management.
Further major signings are inevitable: pounds 50m, the amount which Sky supposedly paid Warren, does give a man a certain degree of bargaining power.
Perez, 31, is the ideal "opponent" from everyone's point of view. Warren is pleased with him because the Colombian, as a former world champion who only last October lost a controversial decision in a bid for the WBA super-bantamweight title, is indisputably a quality performer in whom not even the most assiduous critic can pick holes. Hamed is delighted, because while Perez is still a splendid name to add to one's CV, he has also lost his last three fights and so may be presumed to be firmly on the wrong side of the hill.
The WBA title loss, to Wilfredo Vasquez in France, was followed by points defeats in South Africa and in America to the former IBF featherweight champion Manuel Medina. This suggests that after 12 defeats and two draws in 49 fights spread over 13 years, the fires of ambition do not burn quite so brightly, although enough professional pride and basic competence remains to ensure that he will not be embarrassed by one-sided defeats. Medina is still a top-class contender who could yet regain his title, so going the 10-rounds course with him can be read as a plus rather than a minus.
Perez won his super-flyweight belt in 1989 and then lost it on the first defence to Robert Quiroga in, of all places, Sunderland. The boxing world is shrinking dramatically when a Colombian can fight an American of Mexican extraction in the Crowtree Leisure Centre and still draw a crowd.
It is difficult to criticise an opponent with such imposing credentials but it is equally difficult to see how he can beat a young genius like Hamed. With every time he fights "genius" seems ever more like the only appropriate word to apply to such a breathtaking, original and destructive talent. He has yet to win over many on the press benches; at least one columnist simply refuses to watch him on the grounds that what he does is not boxing but some kind of low-grade wrestling-style pantomime. But they said that about Muhammad Ali.
Warren has already managed to have Hamed installed as the No 1 mandatory challenger for the WBO version of the super-bantamweight title which has the added advantage that, since it is an officially-ordered defence by the champion, the challenger is not obliged to sign away exploitative "options" in order to get the opportunity. The downside is that the WBO title is held by perhaps the best of the four title claimants, Marco Antonio Barrera of Mexico, so it may be advisable to keep the pressure on the other three organisations and delay his title bid until one of them promotes him to the top spot.
At 21, Hamed can afford to wait and pick his opponents. And in the meantime a cagey and proud old veteran like Juan Polo Perez fits the bill to perfection. Hamed should retain his WBC International title for the fifth time but one hopes he will be taken the full 12 rounds and given a proper taste of competition at world level.