Niners have a passing game/QB capable of converting a 3rd down they're in the SB. Instead, their lack of a passing game forced them to need perfect execution in every other area in order for them to have a shot.
They made it far because of how weak the AFC is. Their road to the AFCCG was a first round bye and a Divisional round game against TJ Yates. The reason New England made the SB last year in spite of a partial birth abortion defense was because the 6 starting QBs in the AFC playoffs were Brady, Yates, Flacco, Dalton, Tebow, and Roethlisberger. Roethlisberger is the only QB outside of Brady on that list who's even close to elite and injuries dismantled any chance Pittsburgh had at going on a run.
The 2011 AFC was a historically bad conference. An 8-8 record won a division. The worst defense in the NFL went 13-3 because of how easy its schedule was. 3 of the 6 Qbs in the playoffs were rookies taken after the 1st round or Tim Tebow. The fact Baltimore made the AFCCG without an elite QB does not do jack in proving that you can win without an elite QB in today's NFL. Sure enough, Baltimore lost to the first elite passing offense it played in the playoffs, largely because their passing offense was too ty to hold onto a game winning touchdown. Your "But Lee Evans dropping the ball is the only reason they didn't win!" hypothetical proves my point. Baltimore being incapable of converting that touchdown demonstrates how inconsistent/streaky its passing offense was.
Starting RBs on recent superbowl teams:
2011-2012 superbowl: Ahmad Bradshaw vs. BJGE
2010-2011 superbowl: James Starks vs. Mendenhall
2009-2010 superbowl: Pierre Thomas vs. Joseph Addai
2008-2009 superbowl: Edgerrin James vs. Willie Parker
Why is it that recent superbowl teams have placed no emphasis on an elite running game at all?