Even then, it's not simply a case of tanks being mere meat shields and that's it.
For example, it wasn't until Mists of Pandaria when Druids had Feral and Guardian specs separated. Meaning that before then, they shared the same talent tree. Thus allowing one to pick a role and still be 90% effective in the other role. So, Bear Druids could shift into Cat form when off-tanking and put out DPS level damage.
There also have been several iterations of Vengeance, providing the MT's a massive attack power boost based on damage taken which has put Tanks close to DPS levels of damage (Much to the chagrin of many DPS players who could see themselves being outperformed by a Tank...). In fact, one of the first iterations of Vengeance worked in PvP, which made Tanks one of the best classes for Arena. Especially Protection Warrior who had the highest burst damage of any class in the game and could literally one shot people with Shield Slam with stacked Vengeance.
Looking at other MMO's, it's not always the case of Tanks being meat shields either.
In City of Heroes, Tankers eventually died off in popularity once the AoE limit came in so their easy to attain defences didn't mean much when mass pulling literally the entire dungeon wasn't viable. Instead, people tended to opt for the high damage Brutes or Scrappers instead, if not simply anyone who'd geared enough to get good defences including Masterminds, Stalkers, Arachnos Soldiers or Arachnos Widows (While Peacebringers/Warshades also could get good defences and had forms that increased their tankiness, the existence of Quantum enemies that specifically deal MASSIVE damage to them often made them shy away from the role) if not simply relying on Controllers/Dominators to simply mass CC everything including Arch Villains.
In Anarchy Online, you have 3 main classes for tanking, Enforcer, Keeper and Soldier. With Adventurer having some potential to build for a tank role with a form to supplement it (Though, not often used). But in various periods of time, Enforcers and Soldiers have found themselves at the top of the DPS charts. But that's only notable in specific content, since a lot of stuff was doable with ad-hoc "Tanks". Things like Fixers with their massive evades dodging everything while holding aggro due to keeping several HoTs on everyone in the party. Medics tanking via mass healing and HoTs. Engineers just having their ridiculously high level pet go tank stuff with aggression modifications. Bureaucrats could just charm enemies and make THEM hold aggro. All this without sacrificing on damage potential either.
If looking for a game that supported the idea of tanks as meat shields with little DPS, I'd say Warhammer Online would be the best case. Of the 3 (Technically 6) tank classes, when playing as a tank (With a sword and shield as opposed to using a 2h weapon and smacking things hard) their damage would be rather low, especially compared to the premier damage dealers (Bright Wizard/Sorcerer and Slayer/Choppa... Even more so during that time when Slayers could get a 0.0 attack speed and thus deal literally infinite damage instantly...).
However, as the game was primarily focused on PvP, it meant that the Tanks had instead a lot more focus on staying alive and keeping their allies alive with aggro being less important (Though, still significant when facing Keep Lords). For example, ALL tanks had a channelled skill that would severely reduce damage done to allies behind them, sort of like Passage of Arms but on steroids, making it important for people to actually focus the tanks in PvP. Tanks also had a lot of CC skills so they could stop people from being able to run past them and go murder their squishy allies. Knights of the Blazing Sun and Chosen were the games support classes too, wherein they could provide auras to buff their allies/debuff the enemy respectively (They could rotate them to actually keep 3 aura effects up at once since they persisted for ~12 seconds after being toggled off).
In addition to this, there was keep battles as open world PvP where Tanks gained additional advantages due to the nature of how it worked. On offense, Tanks high survivability meant they could man the battering rams more easily, despite getting shot by ranged defenders, cannons, crossbows or having burning oil dropped on them. On defence, because there was collision, tanks could literally wall off the doorway by standing there, causing the enemy to have to deal with them in order to enter the keep (Until some sneaky buggers zoned in through the back door and murdered all the healers keeping the tanks up)
But again, a lot of this design only worked because it was a PvP centred game. There was nothing like enrage mechanics to contend with. It wasn't considered "OP" to have a plethora of CC that actually worked because it wasn't being designed to be used against bosses that needed to pull off scripted attacks to be threatening. Also, they weren't necessary because you could still do PvP games and take Keeps without them. In fact, you often wouldn't see them, especially given that the lead job designer was a Bright Wizard main so you can imagine what the most OP class in the game was...