On the other hand, chess is a mass sport now and for chess organisers shorter time control is obviously more attractive. But I think that this control does not suit World Championship matches. ↗
What it is saying is that someone who was a world champion and who takes care of himself with a 17-year rest and applies the proper training techniques and perseverance could be successful. ↗
A perfect record does not mean that someone is the greatest. Rocky Marciano never lost a fight, but I never hear anyone say he's the greatest heavyweight champion of all time. ↗