The system works well enough. The problem here is that you consider yourself to be better than you actually are. A quick check on op.gg and looking at your matches history shows that you are always matched with people in either bronze or silver. So you probably are around this elo aswell. And guess what, this is the elo of new players.
Here's the lastest game on the page : https://image.prntscr.com/image/FbUFnLnmSDC5s_9BO9G3Rw.png
You can see lv30, bronze and silver.
Also this isn't "getting boosted" as someone said, Boosting is something related to actual ranked games, not the natural process of leveling up as you play. ; you don't get "boosted from lv10 to lv11" xD
Also people have friends who start the game, and they want to play together. Normal games are there for that; have fun and play with your friends, thus there should be no restriction on that regardless of skill gaps. Ranked on the other hand -where it actually matters- already has this kind of restriction : you can't queue with someone over one division apart.
As you can't decently prevent friends from playing together, there will be instances of games where the matchmaking did all it could to balance things out, but it can't do miracles. But to be honnest these games rarely ever happen anyway.