My response to that perspective is that end product is not defined purely as goals and assists in Jack's role at Arsenal or even Bournemouth.
Jack has played largely as a deep-lying playmaker and peripheral wide-midfielder. He's an intelligent player, with decisive movement and timing. Both of those roles require a lot more than goals and assists. When he played behind the striker, he perhaps showed he may just not be at that elite level for that position on those occasions. That doesn't rule out his usefulness in other positions though.
Yes we would like to see more penetration from him in the final third and better decision making. But there are enough examples of his goals, assists, pre-assists, take ons, vision, aggression and incisiveness to suggest he has all the attributes to be a valuable player at a top club. He needs tuning but that can only come with fitness and games. Who knows how much potential he has already lost?
We simply haven't seen enough of him though. That's really the only thing in true question. The question marks about his goals and assists are based on a sample size that's unfortunately very small. That is the only reason Jack Wilshere is not in the Arsenal squad right now.