@Armstronglivs from "suspect" to "only" to "quite likely" while also casting aspersions at all the other players. That only makes it even across the board: the 24yo doper should be able to defeat the 38yo alleged doper. Which still leaves Djokovic as perhaps one of the best athletes of all time, let alone tennis. Only the GOAT could do what he's doing at his advanced age. He was also coached by the hyper anti-doping Andy Murray who would have never jeopardized his credibility and integrity by coaching a doper. Their relationship was short because Murray is a jerk.
His skill as a player is the single biggest factor and that is only doubted by those with a non-tennis chip on their shoulder or the ignorant. Other greats have had longevity late in their career like Agassi and Federer. Djokovic is doing it because he's unique as a human and better at tennis.