Evokers die because their defensives are largely reactive while they have little to no passive options, as well as deep breath making them rotationally kamikaze into / through mechanics.
The latter is being fixed in Midnight where they get 100% damage stagger during breath.
Everyone has enough defensives to survive the damage they are supposed to be taking, but a lot of other specs also have the defensives to survive (To an extent) the damage they shouldn’t.