I guess a lot of the very high K/D people probably play the game differently to most, without necessarily being way better than others with a decent K/D. I play with a lad who could 100% be well above a 2 K/D, but he doesn't go around looking for kills at all, we always just play to try and win the game. He regularly has 10+ kills in games, but it is just by chance that we come across multiple teams. He wins basically any 1v1 he gets in, if he was bombing around in a vehicle, burning through UAVs and picking people off all game he'd have way more kills. I reckon there are a lot of people like that, who will beat most in a fight, but aren't traversing the map with the sole intent to get as many kills as possible.