Before I started playing League, I had put about 1400 hours into Dota 2 from late 2015 to mid-late 2017 and that was when I transitioned over.
A friend gave me a never ranked level 30 account and I played about 100 games of bots and then went into normals. Whenever I 1st got into ranked, I was maintaining a 50 percent winrate in low Silver, and I just wasn't enjoying the fact that I was struggling at this rank against other low silvers. I knew it was a shit rank and when I quit Dota 2, I was at 4.8k mmr (i think this is plat1-d5/d4 equivalent), so I wasn't used to being at a shit rank.
But one day I queued up and was placed against a Diamond 1 jungler who was smurfing, he was insanely good at the time (and still is) and he just spent the next 40 minutes just shitting on me for lack of a better word. My team told me we wouldn't ff because I didn't deserve a quick loss, I deserved to suffer longer for inting them. After the enemy team ended the game though, I knew that he was better than me, and I needed to become him because of how good he was at the game.
And that's what caused me to continue playing the game and why I keep trying to get better.
Anyway, I'm Plat 1 now and I wouldn't be at that elo if I wasn't inspired by that player to get better at the game.
Realistically, if you think about it, that's the only way for a person to leave low elo. Getting a glimpse of just how bad they are at the game and then putting a lot of effort into getting better.
To comment on why people are toxic in that elo, it's not because of smurfs. You're considerably more likely to get a person that is truly a Silver player than not. I think that elo is toxic (more than others) because people are unwilling to accept that they're bad at the game, so you have players with misplaced egos who think their team is holding them back when in reality they've been in that elo since 2013 and haven't pushed themselves to climb so they end up with 300, 500, 800, 1k games at the end of the season and haven't left Bronze, Silver, and somewhat in Gold.
There's hardstuck players everywhere but it's a known fact that if you spend that much time doing something, you SHOULD get progressively better at it. So I think it's just a mental blockage you need to clear.