Is Faker a good Support or Tank Top in comparison to Pro Supports and Tank Tops? Likely not, because he honed his precision into Carries.
Huni is likely a better Top than Faker, but not a better Player than Faker over all. Yellowstar is likely a much better Support than Faker, who just doesn't have the right personality to Support properly and effectively at a high level.
So no, even for most of you guys in High Elo, you still each have your own tendencies and abilities, and weaknesses. If you were all pretty much 'one in the same' no one would climb, no one would fall. There would be no distinction.
But there is.
Your statement isn't a Fact, it's an Opinion... and a flat out silly one that how one plays the entire group plays. It's illogical regardless of the format.
I do see where you are trying to come from... Pre Made Groups will tend to die together than alone. But in reality, so should Solo. Because if you think "Umm... that Baron Call is a bad idea" and bail... there is no way you can stop 1v5. You might as well have went 'as a Team' and maybe killed enough of them that they couldn't push, or even took the Objective by some miracle of a mistake that was made by the enemy. Because in not going with the Team, you didn't stand together so now you will surely die separately... while your Objectives get over ran by the Enemy.
Which is sort of the intent of all this. To get Solo Players out of a Solo Mind Set and start realizing it's a TEAM. Things like Composition and Strategy matter, and while some times Individual Skill can over-ride through Out-Plays even 5 'I Must Carry' types can effectively communicate to enhance their chances.
A lot of the Toxicity with League came from that 'Solo Carry Mind Set'. You'd get flame for losing Lane... but okay, you're a Mid to Late Game Team Fight Champion. You were facing an Early Game Solo Champion. So now losing your Lane doesn't matter, watching the Enemy fall off because he doesn't scale while you hit your Power Spike just in time to push the Team Fights is what matters. Because while you gave up an Early Advantage you did so for the Late Advantage.
But no, people didn't see that. All they saw was the short term. You lost Lane, so you need to 'git gud'. Instead of "Don't worry, guys. He'll survive, and then when we group he'll be a major part of us Winning". You know... Strategy. Depth. Knowledge of the Macro, not just a focus on the Micro.
The entire idea here is to promote Team Play, to stop this Solo Mind Set and the Toxicity that comes with it.
The draw back is that some people simply are Toxic regardless... so obviously that will carry over. But the great news is, you can choose to never play with Toxics and Trolls again... just group with 4 Players you trust to play the game properly and act like decent people and you magically make all the Trolls and Toxics disappear.
But even if you don't group, working together can still be accomplished (and was, often, in the previous version of Solo/Duo Queue. It's simply a matter of CHOOSING to).
The idea is to get Solo Players to Play as a Team so they can improve more than just Individual Mechanics.