There is a lot of blame to go around, I'm sure, but IMO, Henry and Dombrowski are not at fault. You really can't ask Henry to do more than he has since he took over ownership. Dombrowski assembled a great team on paper. That's all he can do.
This is on the players, mostly the starting rotation, who are simply not performing up to their ability levels. Does Cora have something to do with that? Levangie? Restgate? Strange scheduling, beginning with the 11 game road trip? Possibly, on all counts. But the ultimate responsibility falls on the players.