It's pure luck ranking up

Tell me why every single time i have gotten to promos i have been cursed with complete idiots? I do not even understand how most of them are ranked above bronze 5. There is truly a 15 % chance i get an actual GOOD team who knows the meta and knows how to farm/ not to get killed in stupid spots.

just last game i asked a lee to help early top against a ryze i was nasus and he decided not to ...pantheon comes up multiple times ganks me i cant farm..he goes oh its your fault. Then the game before that i have a warwick support with draven..i end up getting a triple kill and we still lose..It's just pure damn luck.