So your idea of trying to win the game with against an enemy team is to fight the enemy team full force?
That's not the smartest idea.
If you are the ONLY person on your team that is fed then you will be THE ONLY person focused if a fight breaks out. A 5v5 is detrimental to your cause as in reality it is only at max a 2v5 if you have a decent support.
The best scenario is to, again, split, draw the attention elsewhere, and THEN ROTATING to your team so you have a number advantage.
1 of 4 possibilities (not only 4 but these tend to happen the most) happens when you split.
1: The enemy team dives or initiates and gets some kills. All the while you get more gold in minions and exp and you should ideally get a tower or better in the process. Half the time the enemy team is low enough for you to clean everything up if you are "extremely fed."
2: The enemy sends 1 person, sometimes more, to contest you in which case it leaves the mid lane open for a gank, but if not, you at least relieve some pressure and prolong the game.
3: The enemy team forces a bad fight and miraculously ends up losing, leaving the map uncontested for more objective control.
4: The enemy sends all 5 to you, at which point you either notice it soon enough and get out or just run away wasting all their abilities. Once again however, you draw attention away from mid, prolonging the game and relieving pressure for your team.
All in all, it is the best way to go about doing things.
Keep in mind that while the enemy team is all grouped up mid, they are sharing 1 lane worth of gold and experience between all 5 of them, while your team is soaking it up as 4. In the long run, it benefits your team better than it does the enemy.
ALL THE WHILE, you are alone gaining levels are a more excessive rate.
https://www.youtube.com/watch?v=atqd7r_HwnQ