Semantics on my part perhaps. It IS the offense if your two young stars aren't implementing it as designed, or asked for. If they CAN'T do it, then the offense has to be changed so they can. If they WON'T do it, then they need to be forced into an offense where it happens whether they want it or not.
As to the ball doesn't have to be shot to be effective (after a kickout), I disagree to the degree that if the other team doesn't respect the shot, it doesn't create the spacing that benefits the Js. This is the MJ conundrum all over again. He knows that if the ball is in his hands, there is a high(er) percentage of a chance they score. Then he scores a magical number, and the team wins some because 'Michael', but loses often because the supporting cast sucks. Except part of the reason the supporting cast sucks is a lack of rhythm and motion keeping them involved enough to be confident to make the shots. Until the Js learn, or are forced into a more successful style of play on the court, this is a frustrating carousel of basketball to watch. Round and round we go.
Hayward (IMO) left because he saw that the Js were operating as the stars, without the ability to use their gravity to help the team win. He came from Utah, to Stevens for a chance to play a team game with skilled players - where he wouldn't be the only star. He facilitated for a long time, but when push came to shove, for the foreseeable future the ball was going to be in the hands of one of the Js. If that wasn't going to result in a championship, why not go where he can be the guy with the ball in his hand, making more of the right decisions? If nothing else, on a nighty basis that is a more fun game for him, than waiting for a kickout that wasn't going to come, in order to make the right pass. He is also a rhythm player, so the Js style harmed his ability to play as well.
Note: I'm not trashing the Js. I'm observing where they are in this moment of time and trying to assess. If they CAN'T, or WON'T - change the offense so they HAVE to leverage their gravity for the team. If aren't running the designed/intended offense, then that falls on Ainge to change - either by decree, or changing the offense (via changing the coach or whatever), or by moving parts to get the desired result.