Having lost 150ish pounds by diet alone, I can say without reservation that diet plays a massive role in body composition. I probably should have fleshed this out a bit more to avoid ruffling feathers, but my basic premise is that for the average trainee, training right may well be the key to the city. A crappy diet is a bad idea, but there's no way in hell to get big and muscular without hitting the weights hard.
That's actually why the original post is littered with disclaimers and caveats. My initial thought was "Go deadlift until your heart explodes and get huge." Clearly this is hyperbole, and wouldn't help anyone, even if I just wanted to go for shock value, which is rarely my intention. The idea, which I still may turn into something more, is intended for people who aren't anywhere near the level that most of the MAB members are. Lets face it, most of you are stronger, fitter, and more experienced than I am.
What I do know is that by dieting down and not lifting, I ended up fat and weak. Sure, I lost 150 pounds, but no abs, no visible muscle, and 12 inch biceps. On a 6'5" frame. I didn't change a thing in my diet, picked up some dumbbells, worked hard, and added 2 inches to my arms in a couple months.
Back to the diet. I stick with my statement that bulks fail for 2 main reasons. Lack of effort or the ability to eat inhuman amounts of food and still not be satisfied. My self control around pizza aside, a fair bit of it could be fixed by working harder in the gym, on the farm, or loading trucks, or construction work, or something. Its rare to see soft fat people who work their ass off every day in manual labor. They may be fat, but they are strong looking as well. At that point, get the diet in better check and good things happen.
Diet and exercise are intertwined, no matter how much I would like it to be otherwise. But far too many young men worry about every calorie they eat and don't pay attention to their routine. Go eat something, go squat, see what happens.