Sorry for the big picture.
Elo Hell does exist.
Solo queue is not perfect unlike an organized queue.
1. Your first point can be negated by the fact the system doesn't make a distinction between players of similar elos with a lot games under their belt and a few. Your side argue since it's random it fair. There's nothing fair about random elements in a ranked setting causing you to lose. If anything it's highly unfair and doesn't promote an actual competitive system since a random element how player are ranked from the get go.
2. What does my own input or anyone of my team input matter when x amount of players are erasing my carry? The whole argument of this team crap yet one or two trolls on any team is a guaranteed loss for whoever gets them. You can't kill trolling since there is no mechanism and since there is way to make games like this a draw such stats are bogus in my head. No one in this elo system or any should be given credit positive or negative for someone or at times various people trolling a game.
To demonstrate my point another way. This isn't like organized sports at all that assume all of your team players are there to win or at least play by the rules. You get all sorts of trolls at default elo who basically can't play their character or their roles for the game while they feed or more often than not doing nothing until the game ends be it surrender or being pushed in.
3. The distribution of trolls isn't equal. Nor is it something you can peg in the game to make such an argument. Sometimes you could have a bunch of trolls on one team or a lopsided mixture of trolls. The idea that the enemy has more trolls is not supported by any stats riot or anyone on your side is willing to publically disclose.
4. I don't argue I always carry in this style of gameplay as you are going to have bad days. my problem and tons of people on the official forums or places for lol say it the same. Is when you have games where you hard carry only to have it wiped by derpiness due a team that won't win or a feeder. I lose more of my matches because once the laning phase ends and somehow a majority of the team I'm on don't understand that being in 5 man group mid to end game is the optimal. Sorry I don't want play in a mode where there is a clear disconnect between me and my teammates on how to end a game.
It's a pile of crap for a lot of reasons not listed here. Any system that doesn't allow solo players to deal with half the trolls that are in the game be in banning selection or in game is bunk. Hon system is a billion times better and more accurately reflects people usefulness to a team.
Solo Queue is just that and most of it's problems can be resolved by actually being on a team or going to lan tournies. I tried it both seasons and the various time I did I saw crap going on I rarely see in normals which makes me realize it's not worth my time. I play these things casually since I don't have the money or time to travel to play real comp and not random ranked tryhard mode online.