here is why people don't know what they are doing.
exp to lv.30 was reduced heavily, then they introduced missions that reward 500 exp (blasphemy!)
other modes exist which is alot funner (aram,urf) so most level up through that then start getting slaughtered in summoner's rift because of lack of experience.
it doesn't help that they have to play against players with over 500-2000 games played which is unfair, not to mention some players quit for years and play their first match unprepared which leads you to having 3 feeders or more every game on either side of the team.
it feels anticlimactic to win or lose because of unexperienced players or inting trolls that give up on first blood or first few deaths, it's cringy seeiing some people keep playing aggressively and duel the opposing laner with double their farm with a score of 3/0/0+ what makes them so cocky that they could defeat someone with that much lead?
you have to babysit these players every single game, you need to keep roaming and prevent enemies from feeding off of your kids when you have lead or else you're going to lose each and every game, this is mainly why the jungler is a good role to climb since you can gank lanes to shut down huge threats before they grow.
the game was fun before all these questionable exp changes and new mode, new rune updates took place.. but oh well looks like we gotta deal with the broken game where the newer players can't learn how to play due to getting one comboed at lv.2-4 by better players.
if they wanted to increase the damage to make it fast paced, they should have made a seperate mode for tournaments instead of ruining the entire game for newbies.