Please help me understand why this is happening.

In every single game except for about 2 of ranked solo, ranked flex and normals I have played have had players who "Haven't played in two months" and go around about 1/10 by 22 min. Why is this happening to me so consistently? I really don't understand how I am meant to win this "match-made" games. I was climbing consistently and had a win-rate of over 60% on all of the champs i'm playing a lot in ranked and now I'm deranking due to these people. What do I do, plz help.