...and neither have you.
I disagree with the entire premise of why you don't think the Niners are a good running team, but that's OK. I'd submit that if a team knows you are going to run the ball 40 times, do everything they can to stop it and you still average 4.5 yards per carry you are doing pretty damn well.
If you really wanna look at run averages tho then you might wanna look at th average per rush against. Its only 3.9. The Panthers are at 3.7 and the Niners have missed 2 of their starting LBs for a good chunk of the season. Willis was still gimpy before the bye. The majir difference in those total rush yardage stats is exactly what you were talking about before...# of rushes against. My bet is that teams gave up running when they had little success early.
The Niners have also sacrificed run D by refusing to bring up a safety and that has resulted in FAR better pass D. That isn't really evidenced in the stats tho because late prevent defenses have skewed the numbers. Trust me on this tho...a healthy Justin Smith, Ray McDonald, Glenn Dorsey, Aldon Smith, Ahmed Brooks, Navorro Bowman and Patrick Willis are adept at stopping the run.
Finally...stop looking at the statsheet. It's really misleading. The numbers are all topsy turvey due to huge leads. I'm sure the same is true of the Panthers.
The difference is that we don't have to rush well to win. We are a balanced attack and can run or pass. The 49ers struggle if they don't run. And you won't get 150 yards against us. We will stop the run as we have all year and make Kap beat us with his arm. We will pressure him where his passer rater is around 55. On the other hand if you do the same thing to Cam his passer rating is well over a 100 when pressured. And that will be the difference.
Your passing defense is no better than ours. Yet our run defense is better. Plus our passing game is better as are our special teams. Truth is that your biggest plus is home field advantage. Otherwise we match up very well against the 49ers.