This is already the case.
We already as a community condone "witch hunts" when it comes to tanks / healers, in fact it's more commonly done so because a large amount of the time the mechanics are DPS reliant and theres no way to prove that the DPS failed them.
Stop me if you've heard this one before on a wipe:
"Where are the heals!?"
"Healer, why didn't you heal me!?"
"Seriously healer!!!!!!???1111111"
Never mind that the DPS was eating "backhand-ga VII" and the mob in question only uses it if it's failed to be killed / stunned in time.
This game is unlike most other MMO's in that the majority of content is balanced around DPS checks or DPS oriented mechanics. This isn't like a lot of the other MMOs that simply have extended tank and spank fights that can be drawn out due to tank / healer stamina, or even fights that have tons of mechanics that need to be handled and account for DPS players spending long periods of time not even hitting the mob.
Personally i'd love those, give me levers to pull, mobs to position, buttons to hit, floors to jump etc. all of that makes for much more interesting fight design in the long run.
Instead a large number encounters are based on "Do X amount of DPS or you wipe" end of story, like almost all of endgame and a large number of dungeon mechanics ranging from leveling dungeons to Ex roulette are literally this, making DPS an equally crucial role to tanks / healers but the community still has this mindset that they somehow share less of the responsibility. And the best part? The game doesn't even offer you a tool to see how well you are / aren't doing when those checks come up.
How is a tank or healer going to prevent Nidhogg from BBQing the party because the DPS failed to do enough damage before the hard enrage sets in? Do more DPS? Sure, on TOP of already tanking and healing the encounter, surely the answer isn't to ask the DPS to pick up the slack.