The game is so fast and complex that quarterbacks can't come in and prosper right away unless they are truly exceptional. And now, with the growing tendency for guys to come out early from college, after two or three years even at quarterback (to avoid the chance of injury), their capacity for contribution is even yet worse.
You'd have to find someone extraordinary, like Luck, or a highly competent player like Wilson who gets dropped onto the best roster in the game.
I really wonder what the brass thinks of Logan Thomas at this point. A fourth round pick is nothing to sneeze at.