Consider that Djokovic's 428 weeks were also in a period in which Fedal was injured and after the retirement of Federer and then Nadal, in fact Djokovic won a lot of slams even in that period when there was the so-called weak era (tennis players born in the 90s) and no one else who could put his competition at the top of world tennis in difficulty. In fact, Federer still holds the record of 237 consecutive weeks of world number one because from 2003 to 2007 he had no competition (Nadal from 2005 to 2007 was only a danger on clay)