Smurfs in low elo, make it almost impossible to climb
Not nowhere near impossible, just annoying once in while. Also I would argue that P2-D4 has highest percentage of smurfs for populations or games. Don't have data, but just in my experience.
So 4 games in a row
Nowhere near enough games to get anything out of. Hell I even went vs Perkz in plat 2 game last week, but didn't come here ti complain how LEC players ruin plat games.
Overall to reduce smurfing couple things need to happen:
1.Playing in high elo on main accounts needs to be made somehow more rewarding and game quality better. (Maybe just improving of banning trolls might help.)
2.Reducing streamer/youtuber smurfing.