I've watched both 49ers games in their entirety, and I'm not certain Gore is the problem. I mean, when's the last time San Francisco's offensive line got negative grades on ALL FIVE of their players per Pro Football Focus's rankings? The answer is "never", in the Jim Harbaugh 49ers era.
Weeks in 2011, 2012, and 2013 in which a 49er offensive lineman received a negative PFF grade:
Jonathan Goodwin, C - 2011: 1, 2, 11, 13, 14, 15, DP 2012: 6, 10, 13, 15, 16, 17, SB 2013: 1, 2
Mike Iupati, LG - 2011: 1, 3, 5, 6, 12, CC 2012: 6, 10, 13, 17, CC, SB, 2013: 2
Alex Boone, RG - 2011: 1, 2, 4, 5, 13, DP 2012: 3, 6, 8, 10, 14, 2013: 2
Anthony Davis, LT - 2011: 1, 2, 3, 4, 5, 6, 12, 13, 16, 17, DP 2012: 6, 12, 14, 2013: 2
Joe Staley, RT - 2011: 2, 3, 4, 6, 9, 10, 16, CC 2012: No negative grade 2013: 1, 2
The Seahawks D-line got some WORK in against these guys. Also in case anybody is curious, most of the negative grades for these guys are minor negative grades. The O-line under Harbaugh has almost never had a game where most (3 or more of the 5 guys) of the line had a bad day, though opening day in 2011 came close.
I started looking at Seattle's by comparison, and it was too painful, so I stopped.