Guys, this isn't about balance or preseason or any of that, it's just because this game has a really high skillfloor compared to others. I think we can agree that "competent" describes what we see in high gold/plat and above, and the reason that's such a small portion of the playerbase is that there's so, so much a player needs to learn to be competent at the game. The difference between a new player and a gold is orders of magnitude greater than a diamond and a gold, so when you're playing at really high elo, you'll never see someone who's that much better than the rest of the team, but you can easily see someone who's worse. Throw in the fact that it's not that hard to not feed even if you lose lane, and it's pretty obvious that a Challenger can't get as fed off a Plat as a Plat can get fed off a Silver.
I've actually seen this play out in Norms, with a Master tier mid laner who dominates and zones his opponent, picks up 2 kills during laning phase, and comes out of lane with a lead that could decide an LCS game 50 times over. Meanwhile our silver Riven is 0/14 to the plat Gangplank, guess who won that.
Reducing kill gold on feeders was a good step, but if Riot's going to make it easier to win by your skill than your opponent's lack of it, the game basically had to be either easier for weak players, or more forgiving for players who lose lane. One ham-handed way they can implement this is to give turrets a buff that reduces the damage they take when there's only one nearby enemy champion, and a purchasable item that disables this (for splitpushers). That way if a solo lane gets out of control, they can't kill the tower by themselves very quickly, so the logical move for them would be to gank another lane and help push that tower (or get jungler help, but if you want your team to really snowball off your lead the jungler should be pressuring somewhere else). Meanwhile the player who lost lane can stay in lane, maybe buy the item that lets them splitpush and maybe a Zz'Rot Portal, so that they can try to get caught up while their opponent pushes their advantage. A player able to do that would be a lot less heavy than a top laner trying and failing to not feed as their enemy pushes to the inhib.