Confused about how matchmaking works

It seems every time that I win a lot of games, instead of getting matched with and against better players to verify my skill, I end up with really shitty and lower ranked people on my team, while really high ranked people on the other team. This leads to a "forced" lose streak. My mmr was extremely high, about plat 5 mmr, which meant I would skip 2 divisions. However, once I got to that point Riot kept throwing me gold 5 teams and silver 2 teams, while the enemies were all plat. This doesn't make sense for someone who is trying to climb and clearly does not belong in this elo. My question is, how does Riot really balance out the matchmaking? Because I feel like right now it is quite an outdated and neglected system that is ruining the game.