Why am I ALWAYS being paired with garbage players?

So this could be something that could be the answer but I have a feeling it isn't.

I'm new to league (rank 17) but I have almost 1800 hours into DotA 2 so I know what I feel like I know what I am doing. For the passed two days I've played WITH garbage players but AGAINST god-like tier players (compared to me and the rest of my team). I am sure this is bound to happen quite a bit in a low-tier match but the thing is it plays out the same EVERY time. We lose all three lanes because my team has a lack of map awareness, they don't know when or how to gank, I even had players that didn't even speak English and they were the ADC. But that is expected in a game. But the enemy team is like really good. I have had one person in one game who actually knew what they were doing and got not one but TWO penta kills (as Katarina. I'm assuming she is broken in lower level matches.)

I don't get why this is happening to me. I get that is going to happen but there is something severely wrong when it is quite literally every game. I don't think I'm that bad. I've been able to almost carry a team but my team would always just back up at full health. It is frustrating. If anyone has any tips on how to deal with this. Please, I need them. All I have done is get absolutely frustrated.