Survivability is also heavily dictated by cooldown management. If a fight (say a dungeon pull where you’re always taking a lot of damage rather than a raid boss where it’s discrete spikes) takes 20 seconds longer because of poor DPS, that 20 seconds runs the risk of being after you’ve run out of cooldowns. If you’re down 20 or 30% mitigation because of that, your healer is definitely going to notice. It’s better to just put the mobs down quickly before your resources are exhausted.