It's called defense
Let's look at his latest QB ratings:
51.8, 86.5, 29.1, 87.1, 109.4, 76.8, 136.1 & 13.9
Only twice in 8 games did he throw for more than 200 yards, 3 of the 8 he did not get a TD at all.
In those 8 games he has 9 throwing TD's, 2 running TD's and 8 Interceptions. He is average at best. For Gods sake a 13.1 rating against KC, my grandma could do better than that.
Compare it to Mannings:
94.1, 124.5, 122.3, 141.4, 108.8, 115.7, 144.8, 122.5
He has thrown for 200 yds in all those games, twice over 400
In those 8 games he has 30 throwing TD's and 6 interceptions
His game against KC was a paltry 472 yarder with 5 TD's and 1 pick
So far this season, only 25 QB's have higher ratings than Vick