There are a lot of little reasons for the offensive struggles, but I would argue two big ones - Adams and Richard Rodgers. These guys were the 2nd and 3rd round picks from last year. Adams may be the worst starting WR in the NFL and Richard Rodgers may be the slowest starting TE in the NFL. Richard Rodgers at least catches most balls that are near his body - what does Adams do well? He's slow for a WR, doesn't run good routes, has dropped a ton of passes, and whines for a penalty on several plays.
The little things - like Aaron Rodgers missing some plays, poor snaps, fumbles, etc. all contribute, but when two guys that play almost every snap are playing this poorly, you can't expect an offense to be doing well. The margin for error is almost zero.
TT just missed on those two picks. At some MM has to recognize this and try someone else. In the Lions and Bears losses, Adams was targeted 32 times! 32! Those plays resulted in 12 completions for 93 yards, 0 TDs, and an interception. That's a QB ranking of 32 for 32 of the 154 plays they've run. 1 of every 5 plays is going to a guy that's done virtually nothing. Enough.