How does Evelynn manage to be so high of a WR at higher levels but not lower?

The champion has one of the worst early game dueling powers of the cast but one of the best late game presences due to her low base damage (Full base combo at level 3 capping off at a whopping 205 damage + 4% of her enemy's max health), but high ratios (Both basic spells beyond doubling their max rank base damage at as low as 160 AP).

It isn't as though low elo players can't find the right build for her, because other than a scant few off meta builds (raises hand), she builds the exact same five items in both levels of play every. single. game -- , only occasionally swapping out for

With how disorganised lower levels of play are, and how late they go, you would think Evelynn, an isolation based assassin, would flourish there, but instead she sits at one of the lowest winrates while simultaneously holding top 3 positions for a year and a half at diamond+

It isn't just a matter of being able to run wild at lower levels either. The same condition of "just cc him" applies doubly to Evelynn, who can't cast half her abilities while snared and who has among the lowest resistances in the game. Both champions have a very straight forward gameplan when they start going off as well; Evelynn doesn't even need to land her charm or Q1 once she reaches late game, but the shorter games at higher levels should lead to her not being able to do anything just as it does for . Yi is weak against early invades? Try tussling with an / / / / / level 3 when your entire combo doesn't even hit a third of their health before going on an 8 second cooldown. And yet she still sits at a comfortable 51% wr early at diamond+ before 15 mintues.

So what is it about these two champions that I'm missing?