Why do i keep getting put with bad teammates

Its getting pretty annoying, and im also getting tired of this boring bad elo, its the same cycle over and over Again, stomp lane, Watch enemy team stomp your team, get 1 shotted by á fed enemy your team fed, Watch enemy team finish the game, lose the match with 70000 dmg which is more than your Whole team's dmg combined, derank for performing...too good?