"Excuses are like assholes, everyone has them" but no seriously man. Stop focusing on everyone else's mistakes and start looking at your own. If you can grow as a player, you will rank up. You may not think so because you are still focused on the idea that having a feeding teammate means you lose by default. But if you start thinking about all the little things you could've done better, you could probably get out of bronze 5 within a week.
Example: 1) its no big deal i dont have a trinket, they have little effective in the game. -Wrong, if you have an upgraded yellow trinket + a pink ward thats 3 wards you can have on the map all the time for pretty much the cost of upgrading your trinket for 250 gold.. More vision = less people getting caught.
- My CS sucks, but at least everyone else's does too. -Wrong, they have shitty CS because they belong in their division, If you honestly think you are better than these bronze 5 players. You will out CS them, It is important. EVEN if every1 else in the game is sucking at it, YOU have to bet the better player and have more.
3)I missed my ult, but its okay so did my teammate in a previous team fight. -Wrong, If you wan't to win the game, dont make these mistakes. Don't make excuses or try to justify your feelings by comparing them to someone else on your team. YOU made the mistake, you are equally at fault for the loss.
4)I'm fed and i tried to make a big play but failed but its okay my team is feeding they are lucky to have me and should cut me some slack: Wrong-, I could be 25-2-15 in a game while the rest of my team is struggling, it is MY job to carry them since I have the farm, if I fuck up, I could cost the team the game. Regardless of how well my team is doing or not, they are depending on me to use my gold wisely, so don't be careless once you obtain a lead.
I Know you didn't say anything about 3 of these points, but I know people do it all the time, I went on tilt, went from s2 to s5 in 1 night, my MMR was so trash i was getting 11LP a win and losing 29LP, I was playing with bronze 4 players in a few of my games I KNOW what it's like. Think about these points.. Think about yourself.. And don't worry about your teamates mistakes. You guys all make an equal amount of mistakes, that is why you are all in the same ELO. Think of your rank as the amount of mistakes you make rather than how good you are. The higher the rank you hare, the less mistakes YOU make.