At the risk of necro'ing a dead thread, this happened to me in the final MSQ dungeon of Dawntrail's first boss. Healer and other DPS almost immediately died due to failed mechanics. Myself and the tank were all that were left and this particular boss has a mechanic where there's a simultaneous tankbuster and stack AoE. I used Feint since it's the only mitigation I have as a VPR (easily could have managed if I was on a NIN with access to Shade Shift), but the tank didn't use Reprisal or couldn't because it was on cooldown.

Predictably, I died. And I released because there was no way the tank was going to try to solo this thing from 65%...right..?

Now, if you know the final MSQ dungeon, you know that the boss rooms are actually locked off to the point where you can't even see what's going on inside if you're not in the arena. The entire party proceeded to stare at a wall for the next seven minutes, and what do you know, the tank choked at the end and died anyway, destroying other people's time.

I know the prevailing argument from hero tank defenders is "Oh, you shouldn't have died, so let me have my fun." It's absurdly easy to stay alive and tickle the boss to death, especially when you've had almost a hundred levels to learn healing and mitigation mechanics. And sometimes it doesn't even matter if you do the fight right, unavoidable damage is harder for a DPS to overcome.

The near immortality of tanks is the problem, especially when a fight with tankbusters isn't enough to bring them down to dangerous levels. You aren't doing anything fun or truly challenging like soloing a raid boss from a previous expansion with clever mechanic avoidance and near perfect execution over a long fight. You're fighting a dungeon boss that repeats the same two or three mechanics over and over. If you want to solo content, solo content that you can queue for solo. You're cannibalizing three other peoples' time.