I don't think there is a 240 pound LB in the league that 17 would not catch. As others have said, he is very fast. He can run circles around virtually any LB.
As for LVE, when he was ahead of 17, he wasn't close enough to actually block him and 17 blew by. By the time LVE could reach him he could only hot him from behind, so he let him go to avoid a penalty.
The instant Smith was tackled, I knew the Cowboys would only get 3 points out of it. Because that's what they are. In that situation, winning teams get 7, losers get 3