Bronze and Silver can reliably crawl out of Bronze, but I can absolutely tell you: in the current run meta, it's going to take 3 times the amount of games/time than if a Gold was trying to progress to plat while already in gold.
Even if you're a hard carry, the game's current incarnation doesn't allow super carries in near enough bronze games to pull yourself out unless you're a 1 trick assassin or 1v5 adc like Tristana. If you play anything else, you can expect to be having 50 minute games every game, hyper feeders, and many of the situations won't actually offer an objective carry or a kill carry.
Something else to stress: Gold players may very well fail hard compared to Gold tier games while in Bronze. As you climb, your expectations of your teams and momentum behind your pacing changes. If you are used to Gold momentum but are playing in Bronze, it's very likely you are used to a game beginning the team momentum around 10 minutes. In Bronze, the Momentum is often set at FOUR minutes - 6 Minutes. If you fully expect to be able to farm for 10 minutes and have a responsive team, and the team collapses by 4 minutes, sometimes you don't have the option to keep on farming, and have to attempt to save a flood of lane tidal waves by abandoning it. Without the farm though, you begin to get pulled down behind the team. And if you attempt to go back to farming, your farm is usually destroyed anyways because the mid pushes have begun at ~ 8 minutes and there just is so much pressure that you can't farm without risking dying.
I know that when I play with Plat/Gold players, I know that skirmishes are fast and reactive, but farm lanes are peaceful and relatively aware.
When in Silver, I generally know that skirmishes become full game skirmishes where the team completely forgets about farming or defending and just chases kills. I know that farm is anything but peaceful, because lanes are never aware, push out, don't know freezing, and feed so fast that often your lane (the only intact one) becomes a 1v4 quickly because the feeders won't even come try to defend it with you, but rather start raging and trolling, and feeding the already fed champs they created.
You might spend ~100 games from Gold V to Plat V. You're going to realistically spend ~300 games from Bronze III to Silver III. And time is finite; you only have one year, you have jobs, and possibly families. If you have to use that many games to climb, it might as well be elo hell.
