Well that's three years in a row now where Seattle's run defense was stellar in the first half and weak in the second half. And Pete's been here three years exactly. So that's something to ponder on.
In fairness, Seattle's faced some good running backs in the last 5 games. If they are getting gashed by Steven Jackson and whatever Arizona is running out there, then I'd get worried.
Steven Jackson is still one of the best backs in the league though - but that said, we've contained him well in the past, so I'd be miffed if he runs all over us.
Also, whilst I agree we fell apart in 2010, we lost Cole, Bryant and Mebane for sustained periods - last year our Run D was solid down the stretch, forcing Baltimore to throw 52 pass attempts and limit Rice to just FIVE carries, two games against St Louis where we kept Jackson quiet AGAIN (in our first game we limited him to 42 yards in one game, with 19 of those yards coming on a 3rd and 26 run - and in one drive in the second game, we stopped them 7 times in a row from our own 1 before FINALLY succumbing),
we held LeSean McCoy to 84 yards, Kahlil Bell (lol) to 64 yards, and Frank Gore to 83 yards on 23 carries (3.6 yard average - though Kendall Hunter gashed us for 73 on 12 carries, but the 49ers are one of the best rushing teams in the league, and allowing 156 yards on 35 carries to them isn't the biggest crime in the world), and Larod Stevens-Howling to 93 yards. In fact, we allowed just one 100 yard game in the final 8 (Roy Helu, with 108), in a game where our defense simply couldn't stop anything.
I would hardly classify that 8 game stretch as "falling apart", all thigns considered.