1 step at a time.
First - You're saying you have the ability to tell when an opponent is purposely AFK, RQ, or DC. While it IS more obvious as time moves on, a player can do these things for small periods of time, which go unnoticed. A player can AFK farm top, avoiding dragon and botlane's easy inhib, hurting their team. Can you explain to me how you're going to notice that such a thing is purposeful?
Second - You're saying you've got 2 of a type of troll out of 54 games. That's a pretty good experience, overall.
Third - It's not easy to notice when a player is purposely trolling or intentionally dying. Sometimes a player is bad, sometimes they are trolling. There's no CLEAR list of qualities to distiniguish the two, only extreme behaviors that make intentional trolling clear to others on the enemy team.
Fourth - We're now talking about you as a credible source. I could be wrong, but "I have yet to see" doesn't make it the absolute truth. It just means "As far as I could tell", which means you could be wrong in your interpretations.
Fifth - Everything you've described is how you interpreted it. I'm saying that you're too confident in your ability to tell what the opposing teams intentions and actions are, and need to reevaluate your viewpoint.
Given that you're only 2 wins away from a 50% winrate, which is a good winrate to climb with, you should really be the kind of player who comes in and repeats my advice, since you've been doing really well, DESPITE having the trolls, afks, and dcs only ever being on your team. You even had a 7 game win streak recently and have a 66% winrate for the past 15 ranked games.
Despite that, you came here to complain about how unlucky you were. It honestly concerns me that despite how well you're doing, you've got such a negative viewpoint and suggest that people may just be unlucky, when you yourself are statistically lucky.
Clearly things "even out" if you were able to hit Plat 4 in 50 days after being in low golds and lower for such a long time, right?