Who is this game balanced for?

I know Riot has said that we in low elo don't understand game balance fully as the game is balanced around plat+ but this problem REALLY needs to be addressed.

The skill floor / power spikes of assassins doesn't feel balanced. I am consistently frustrated playing against them. You can buy boots, sit at tower and get 0 cs, hit level 6, roam somewhere and clean up a fight, and that really is factual. I understand that you can do flashy things with Zed and LB, but these things are in on way a prerequisite to be successful with them.

I believe the power spikes of the assassin class are achieved too early, and achieved far too easily.

I would rather see the base damage lowered and the ratios increased so they are at least dependent on some sort of itemization, which they really aren't. This is why we see things like tank Akali and cinderhulk Fizz. Or, have the base damage of their damaging abilities scale slower on ranks 1-3 but spike harder at 4+, this way it's not, "I hit level 6 and can 100-0 this poor TF who can't farm cause I'm LB" but "I'm now level 9, he is halfway through abyssal, now I need to win more than a single trade to kill him, work around his cooldowns, etc." I would suggest the level 16+ scaling be very high, at that point let them one shot people unless they're chain CCd instantly, but should that really be an option for them literally 6 minutes into the game?