When the scheme is to have your play maker stand in the corner and shoot... then it doesn't matter how many playmakers you get.
Now the scheme could be lue's fault or it could be Kawhi and PG are unsigned going into next year so you better let them do whatever they want. It could be Harden deferring because he is new or Kawhi saying this is my team so this is how it's working. We really don't know.
It's because it's a forward looking projection system with seasonality that's supposed to determine the value a player gives on a neutral court NEXT game. So if this number of games into a season Embiids value as determined by the algorithm (its a black box btw, unlike BPM where we know how it's calculated) drops a little bit it'll be reflected into his EPM. Or if the algorithm thinks that Embiids value dips after a few good games his EPM could go down because he had good games. Or the opposite could happen with SGAs.
The creator said it takes into account both of these things on a podcast. Which makes sense as DARKO is meant to be a fantasy projection system for betting. However the creator has stated he has never been able to make money with it. He states the reason why despite it working with backtesting is that line movements aren't figured in.
TLDR should never be used to determine who has had the better season so far, since it isn't designed to answer that question. However on here it's what it is used most often for.