It would seem a lot of people have incorrect information on what a "throw" is
A THROW is when you constantly dick around and eventually set yourself behind to the point the enemy catches up and wins, regardless of how hard you stomped early game.
What a lot of people experience yet for some reason call it throwing is when you get OUTSCALED.
If you are
and you go vs

and see yourself losing the longer the game goes on you did not (probably) THROW the game you got OUTSCALED.
The enemy teams late game is better than yours it's as simple as that.
Another thing people don't seem to understand is TEAMFIGHTS ARE NOT THE ONLY WAY TO WIN
If you see yourself behind in the game DO NOT (unless your team comp is great in it) TEAMFIGHT. Pressure all of the lanes/objectives. Farm. Catch up. Get picks. etc. Do not go head first into a battle royal mid lane against the enemy team 20+ kills up on you. That's being stupid.