Apparently being placed bronze means being eternally placed into a team that just doesn't know how to play the game.
It also means being placed AGAINST such teams. If you can't win in Bronze, it's either a sign that you can't adapt to your teammates (which can be hard if you are used to better teammates and is a skill in itself), or that it's your real level.
But the placement system is definitely not broken. I was placed in Bronze 3, and I definitely not play like Bronze 3, but you are intended to be placed lower than your real level at the beginning of a season so that you can climb over the year, and not just bounce up and down around the rank you deserve all year long.
I can't even dream of climbing out because players who are good at the game and are also climbing always get placed on the enemy team and yet my team is almost always filled with players that dont play more than one role, have never even seen some champions, and are playing on toaster ovens for computers.
Of course you can dream of climbing, as I just said, that's precisely the purpose of the placement system. You can have a streak of bad luck, but this above cannot hold true if you play enough games. Just continue playing a bit more, and statistically you'll have the good players on your team and the oven-for-computers as opponents just as often as not.