You would think NFL teams would learn by now how important it is to invest in the offensive line. Guys like Tim Couch and David Carr had their careers ruined because their lines couldn't block. Not every team has a guy like Russell Wilson at QB who can still be damn good despite poor pass blocking. More often than not if you can't protect the QB, you won't go anywhere and you will waste whatever talent you have at the skill positions.
Sometimes the lines get blurred too, holding the ball too long or not making the reads fast enough can make an o-line look bad, when really the ball needs to be gone and out his hand, getting greedy looking down field, lack of pocket presence sensing pressure, hold it afraid to throw a pick, happy feet. That's probably the biggest adjustment for a qb going from college to nfl is the speed of the game the speed of the defense, and how much time they had to throw in college is night and day compared to nfl, the windows are tighter receivers aren't as open as they used to be, there has to be a massive amount of anticipation and that's why they study so hard in the film room at the pro-level, to attempt to know what is going to happen before it happens.
Even for the best improvisers in the game, we saw it in the superbowl with mahomes, the bucs were able to put pressure on him before he was done searching down field, made him uncomfortable, while they had gameplanned focused coverage into areas that they highlighted. You can only create so much on your own, that is why it's a team sport, eventually you need the protection and time in the passing game in order to have success, and that holds true for even the best in the game.
I think most nfl gm's know their deficiencies, it's just how they choose to address it or don't address it sometimes is mind boggling, when it clearly is an o-line issue and glaring need up front, they decide to draft a skill player, thinking they'll address it thru free agency/later rounds. Lions used to do that often, Bengals recently opting to draft a wr with their top 5 pick instead of ol selection, yeah you need weapons that can get open and make big plays, but it's meaningless if you don't have the time to throw, and they've struggled in that area. At least they came back and drafted ol in the 2nd rd though, so sometimes it is a tough decision how to fill needs if you have your eye's on a player that you feel will be a good fit/impact player.
Just my take on it.