And my point is this, you cannot specifically just look at a specific attribute and say that if only this has gone down, then there is decline. Decline can come in any form and then loss of other attributes only compound and accelerate the decline even further.
Now, you can say, and I would agree that Djokovic's decline hasn't been as steep as Federer and Nadal, but that doesn't mean Djokovic hasn't declined from the lofty standards he brought week in week out.
This is meant to be a weak era right? So explain to me why Djokovic is unable to go week in week out againt supposedly weak competition and make the final at least of every single event he plays, like he did from the Paris 2014 to RG 2016 period? Why is he losing matches early at IW and Miami, even when he won the last three slams...why are his clay results not what they once were? Why can't he win WTF since 2015, when had won four in a row?
The peak Djokovic was ruthless everywhere.