What is the impact of a good support in a Ranked Solo Queue game?

It is true that you can win a game as a carry easier than you can as a support, but your team might get screwed over if the enemy team has a support and good carries while your team just has squishy carries. The support's role is to make sure that at least one of the carries gets fed enough to win the game for the team. That isn't to say that a team with no support character will always lose, but they may have done better with a support.

Ranked Solo Queue is a real pain for support. Even if you're good at it, it's not really obvious that you'll get in sync with the carry. To be really efficient in ranked game, you need a sufficiently reliable carry. There you can make a difference because you'll get him fed, get him kills and farms, saving his life multiple times. There is the true support strength.

Compared to the same carry with a bad support, you'll win. But don't get wrong, you won't carry the game. Your carry will do it for you. You play support or you play carry.

The real pain in ranked game is that you will probably get matched with bad team-mates (at least at start) that do not get the real principle of what a support is and are just hoping to have a mobile health pot at their side. They are hardest carry to support, because they don't know your strength or weaknesses and will fail by assuming too much and not taking you into account whether it be mana, cool-down etc. ("Where is my heal, where is my shield, why no ult?")

The best experience I had in ranked game as support is with a duo partner that can carry for me. Sometimes works too with a duo in another lane, or jungling, because you still can synergise during mid-game, ganks and team-fights.

But still, support are the key of many games, but games where people know to play their champion and their role. Bad carries makes bad supports.