[pvnk]

Can always use Flash.

Yes, but other ADCs are more viable when they have an escape because ADC is all about micromanaging and constantly repositioning. You can't reposition with Ashe without the use of flash which is every five minutes. In that sense, other ADCs such as Vayne, Caitlyn, Lucian, etc can easily outduel Ashe and also have the option of escaping if they aren't winning a 1v1. On top of this, Jinx is essentially Ashe with a snare and more damage + attack speed.

Let's not even talk about the assassins with gap closers and resets that target specifically squishy champions like Ashe (one of the squishiest).

When I see an Ashe on the enemy team, it's 100% my target. Pop. Pop. Pop.