IMO, it's all of the above to varying degrees. Yes, we have a young, seive-like O line. However, there are plays that can be designed to minimmize that. Is AVP calling those plays? Are they even in the playbook? I think at least some are. It was noteworthy to see our 2 backups play in the preseason and suddenly start theowing mid-range passes.
Bottom line, though, Trent absolutely has to throw the ball deep. Whether TO or Lee are covered, it doesn't matter. Whether the ball falls incomplte, it doesn't matter. The line has, at least some snaps, given Trent the few seconds needed to dop back and throw the ball downfield. By not throwing deep more often, Trent is only making the defense defend about 20 yards - effectively putting us in the red zone for the entire game.
And of course, Jauron is to share in the blame for all things. He's taught this team to not take chances, to take what the defense gives them, to accept losing provided they learn from it. He needs to put a shock callar on Trent and zap him every time he throws a checkdown, plain and simple. Ultimately if he can't see that this is the biggest problem with our offense and he doesn't do something about it; he should/will be gone.