I can't really say with any certainly what the real reason behind that beatdown was, because it's really staggering to imagine that the fluent and smooth Broncos offense was completely obliterated. I can't place all the blame Peyton, I can't place all of the blame on the coaches, I can't think it was just one of those factors — it was basically everything. They were just shattered and the Seahawks smelled the blood in the water. That opening play safety was really the crux of the initial problems with their offensive coordination, and it didn't get much better from there.
I do think though that coaching has the most to do with the systematic breakdown of the best offense in the league, they had no contingency plan. It didn't seem like, to me, they expected to run into the freight train that is the Seahawks defense. It looked to me like the Broncos did nothing to prepare for the game they were going to have. Did Peyton choke? Yeah, kind of. Peyton's decision-making was poor to say the least, but a lot of the blame on that front has to go down to their initial gameplan, which seemed utterly destroyed after they took the field.
Case in point here, I don't think the Broncos were ready at all, and they got completely dissected by the better team on the day they were hyped up the most. Broncos sure didn't "beat themselves" or any of that hyperbole, I truly think that the Broncos just weren't prepared for anything that game, which tells me that nobody knew what was coming and just how frantic it would be for them. It's certainly strange, because they were a great team all season until this point and it was apparent how good Seattle was all season long. How did they not expect what they ran into? It certainly seemed like it, with just how overrun they got.
It's not like the Broncos were outmatched either, they have a lot of talented players on that team. If they played their best, I think they could have beaten the Seahawks, but were absolutely off-kilter all game long. To blame crowd noise, like Welker says, for an explanation for the breakdown is foolish to say the least. ADAPT. They needed backup plans and they needed to know how to adapt with the worst situations, they didn't and they lost. Big time.
If I were a Bronco fan I would definitely want the front office to look at the coaching staff, starting with John Fox, because while he did lead his team to a Super Bowl, he got dismantled in a way that I don't think I've ever seen in a championship game before. Total lack of control, that entire game. What a mess.