The weeks are going to continue to rack up, even when he loses it at some point, he is still likely going to regain it again as he continues to go deep and possibly win more slams.The year has gone about as well for Djokovic continuing to add weeks as it could. His only real competitors for YE No. 1 assuming Djokovic has a routine year for him is Nadal and Medvedev unless someone like Rublev or Tsitsipas has a real breakthrough year at slams.
Nadal added nothing at the ATP Cup and has lost points since then. He is still the biggest threat for YE No. 1 in my opinion, but the five times he has gotten YE no. 1 are all years he has won 2 slams. With USO going to a faster court, I just don't thing that is likely to happen this year or ever again.
Medvedev has chipped away a little by doing well at ATP Cup and getting to the finals at the AO. But he really missed an opportunity by only adding 90 points at Miami. While he did well at MC the last time it was played, I just do not have much confidence that he can really suddenly become a great clay courter or grass player. Even if he does somehow gain enough points to take over number 1, it will be brief because he has so many points to protect from Cincinnati on.
I think that all the other players are likely to split points among them allowing Djokovic to maybe continue to be number 1 the whole year and into next year. He is unlikely to have 16,000 points, but keeping no 1 for as many weeks as possible is great for his resume. If he does stay no 1 all year, I believe he would have 352 weeks at number one. I am hoping he can actually be the first to 400 weeks, but that may be hard because he is not focusing so much on this record any more.
At this point, I have him guaranteed at 322 and likely many more.