The matchmaking in this game is pure shit, that's what it comes down to. Wanna know something that legit sucks, and I'm serious this is true: if your MMR is high, like say you are in Silver but won games too fast and got Platinum MMR, you are going to get matched against plat players in your PROMOS! That shit is true, and so to get into gold you have to beat platinum players, that is 100% the way their system is designed, not even any low down dirt, so that gives an idea how completely cow flop Riot matchmaking is.
What you had wasn't even very bad, tbh. I could only dream to be lucky like that with having games only THAT GOOD as you think the last one is bad. I just had 5 games in a row in Poro King that even God couldn't carry the teams I got matched with. Two games had TWO AFK. Btw, game before those 5 was also TWO AFK, and we won with 3 v 5 thanks to me and another guy carrying super hard. I was easily strongest on the team in EVERY one of these 5 uncarryable games in a row. One game I did most damage to champs, tanked most damage, and had by far the best KDA -- out of BOTH teams -- and we still got rolled.
So, yeah the matchmaking is complete shit. But what you posted almost isn't even bad, it's like you must be on a good list or something. If I had it that good as what you consider bad I would consider myself extremely lucky to get games SO GOOD. Sometimes I think this game has me on a shit list or something with what I get matched with.
Keep calm and carry on.
[slayer-pantheon-thumbs]