Olynyk will never change, he is what he is. He's glued to the floor, he's still an up fake machine, because he's frightened to get his shot blocked, he has to be one of the least athletic bigs in the NBA. He doesn't rebound, he's suspect defensively. His "point guard" skills show too seldom to be admired any longer. Kelly must not be signed at all.
Amir is just not a physical player, he's easily dismissed with one arm by most bigs in the league. He's visibly slowing down before our eyes. He has little energy, or offensive game.
Zeller is useful on the offensive end, and soft and just not effective on the defensive end. He's an end of the bench big on most teams. Like Kelly, he should be thankful he's 7 feet.
Jerebko is an ok backup being paid about what he's worth. At times he looks like a bargain, and other times he's invisible.
Mickey is young and looks lost and ineffective.
Answer to the OP question...a frustrated YES.