To learn DD role, i made a 4 pet magsork 1 bar build, which is probably the laziest DD build.
In my dungeon runs as lazsork DD i do around 50% damage with other sub-50 DDs, around 15% with post-160 DDs. Problem is not how much DPS i do, its that i am not motivated to do more damage than required. I know some people can push 120K DPS on a trial dummy, but practically dungeons are passable with 25K DPS per DD.
For example in path of exile i played necromancer with a crowd of zombies and spectres, so my only task was looting. ESO lacks summoner DD class, even with 4 pet sorc i have 8 damaging abilities to use.
I've done vet DLC dungeons with total 30k team DPS. Its just my estimation that 25k DPS for DD should be enough.
I will change my question: what makes you strive to do more DPS than required?
I did vet Frostvault with 30k total team DPS (both DDs were PvP build), it took around 15 minutes to kill the last boss.
My newbie lazsork does 8k DPS right now and its enough for normal dungeons. I have a feeling, when i get armor sets i will be still dealing bare minimum damage.