I havent played season 8 too much,so I dont know if it was always like this.
But lately most of my win happen because my team is good,not because of me.
When I play tank,if my team doesnt follow I die.
If I am ranged when my team doesnt engage we lose.
In every single game I'm in the top in some category,but I still lose because my team cant follow my pace.
Match making is failing or buffing tank and nerfing damage is making this game much more luck oriented(team making).
*or I'm just too naive and hope riot care about normal player games instead of lcs*