To be honest, to answer this question, you have to ask yourself: what is a carry?
Is a carry someone who does the most damage and wipes people off the map?
No. A carry is someone who contributes immensely to winning the game. Whether it's that Jarvan with the flawless baron steal, that 0/5 Sona with the 5 man Crescendo, or the 36/0 Katarina that 1v5s and melts the team. It doesn't matter whether it's that Vayne who positions flawlessly and demolishes people, or that Thresh in the background setting up the lanterns, hooks, and flays. There's no difference between a carry who spends their gold on a Sightstone, and a carry who spends their gold on a Blade of the Ruined King.
KDA doesn't matter. Winning does.
To me, the jungler I respect the most is FNC Cyanide. He's willing to play the sacrificial lamb. He destroys the most wards, plants the most wards, dies a ton, gets very little kills. Most people below Silver would call that feeding. But honestly, Cyanide is one of the hardest carries in Fnatic. His KDA is atrocious, but he's still a fantastic carry. I'm sure most people would rather have Cyanide than a so-called "carry" like Reginald, who has a decent KDA but terrible decision making and mechanics.