Please notice the "Trubisky also ..." part. That says that there are all of these horrible things happening with the offense and then you add Trubisky not playing well either.
To make things clear, get Belichick and let him choose his offensive coordinator plus his starting 5 offensive linemen from any place on any roster in the NFL, etc.
Trubisky is STILL going to have some major problems.
No one gets a free pass on what is happening with the Bears' offense. Not Trubisky, nor Nagy, nor the offensive coordinator, nor the offensive line coach, not the offensive linemen, nor the TEs, nor the QB coach, nor the TE coach, nor the WR coach, nor most of the receivers (Robinson is the only one with a chance of getting a pass and he might not either), nor the running backs as runners, receivers or blockers.
Take any one of the ones mentioned above, have them improve and the offense becomes a little bit better. I understand that with Nagy getting his play calling out of his ass, with the offensive line blocking better and at least trying to sell the play-action run, the offense can improve a ton. So too can it improve a ton with Trubisky not playing scared or over and under throwing his receivers.