Teemo (Tanky AD Teemo) does just fine in team fights in the right comps. He was on the winning team at Dreamhack a couple of times. Kind of a niche champion, but he gets the job done when he's used right.
Also, teamfights will always happen, or you're going to be giving away towers/dragons/baron for free. And if you don't join in, the other team will gladly engage on a 5v4.