15-1, two home games to get to the Super Bowl, you like the odds. It was certainly in the window of opportunity talent-wise.
But this was not great football team. "Just outscore 'em" makes a team especially vulnerable on "any given Sunday".
It came down to the character of the passing defense. The 10th. ranked 80.6 passer-rating-against is superficially good enough when coupled with a high powered offense, but when you scratch below the surface we can see the problem.
That 80.6 was as low as it was because of the insanely high 31 INTs. For perspective, you have to go back to the 2005 Bengals to find a team matching that number. At the same time, this defense was dead last in passing yards surrendered, 27th. yards per pass surrendered, 27th. in TDs surrendered and 19th. in completion percentage against. That defense set the all-time NFL record at the time for passing yards surrendered. If I recall correctly, they also set the record for +20 yard pass plays. These statistical extremes sync up with an eye test that says this secondary was a risk taking, rout jumping crew, vulnerable to exploitation. Losing Nick Collins might have been the difference; a glue factor that might have imposed better discipline.
So, what happens if an opposing QB has a hot hand and you don't get those 2 or 3 INTs? Eli Manning has always been a wildly erratic QB, looking like a world beater in one game or season and a bum the next. The fact he had a hot hand that day exposed the vulnerabilities in the secondary. Also, that Giant's defense was jelling in the last couple of games of the season, got in the playoffs as a 9-7 team, and then rolled to the SB win clicking on all cylinders. In the last 2 regular season games and the 4 playoff games, the Giants didn't give up more than 20 points.
Now, the Packers lost the turnover battle in that game 4-1, with 3 fumbles. If that doesn't happen the Packers just outscore 'em? Maybe? Probably?. But what happens the following week or the one after than with that vulnerable pass defense?
Green Bay in 2010, this Giants team, the Ravens the following year: hot handed QBs with good defenses, teams on a roll, coiming out the wild card. In 2011 the Packers ran into a buzz saw with a major exploitable weakenss.
Lets consider the current Rams team. Are they a good team? Sure. If they finish 15-1 does that make them a great team? No, it does not. The team you saw playing the struggling Packers is who they are. They score a lot; they're disciplined and resiliant but not great on defense. That Packer game was not some trap game or let down. The Rams have pass defense vulnerabilites if not quite as striking as that 2011 Packer secondary. If some "lesser" team with a good defense and a QB having a good day knocks them off would I be shocked? No. I suppose that Rams D could jell into something better it the could be a great team. But not as they stand now. And if they don't they will be vulnerable.