I said this on another thread, but yeah once you get to gold+ people act like potatoes when they do bad. This happens a lot in NA because we have a very small amount of people playing competitively. Understand for all the people playing we only have around 1.1M players playing ranked and some users have more than one account.
In addition as long as you are above 50% of all players which I believe is at silver 3, then for the most part all players below you play worse and in addition to this there are more people who play worse than you than better. Then lets bring up the idea that there are other factors that this game has like what you are talking about, which is the willingness to cooperate, listen to others, create comps, latency, ping, etc which will take the people who are supposed to be at least even to your level and juice that number even smaller. Then the champion skill cap compared to the champion's max efficiency can be brought into question.
Yep it's an uphill and wickedly hard and unfair battle to move from gold and platinum to anywhere higher because if you look at the numbers that is what they say. You might be wondering as a high ranked person, "When does the game get fun and when do my allies get less stupid." The answer to this is never. Go watch streamers, you'll notice the same shit all the way up into masters. That is why professionals feed you the shit pill that you need to take responsibility to carry the game, because well... unfortunately what else is there? If you are a shining star in a dim and dark galaxy then you need to shine the brightest. I really don't like the idea either but that's why people talk about balance and character skill level/mechanic requirements,, itemization, and counterplay.