Queing as a DPS means you should have other things to do while you wait. That has always been the case in every game I've played. In EQ, you'd spend a good chunk of time spamming for a tank or hearer and groups would just disband if you lost one they were so in demand. And WoW has the long wait times like ESO is gaining. In both EQ and WoW, that fast turn around for tanks and healers came with a price. You were held responsible for every single mistake that happen (and many times it wasn't theirs). You got blamed if the mob even touch someone as a tank. A death would bring pure hatred. I don't think players who played only dps understood how much like work it could feel. So its no wonder most just didn't play those.

ESO has been different in that the content isn't as hard but its probably going to go there but perhaps for a different reason. In EQ, a tank and heal class literally is useless in solo gameplay (why mercs were introduced). WoW is more balanced in that area by allowing you to carry two specs and the same time. You just switch and the game changes you to your dps setup. If ESO game play is more difficult, its in the devs not having decided where they want the classes to be and you will be expected to switch out up to twelve pieces of gear (or get an addon that will do it for you) and change you points. Basically all the things that many of us would just rather stick to one thing and wait. But there's this undercurrent that they don't want a dedicated tank or healing class. Everyone can do it so of course almost every tank and healer we meant is going to be subpar due to so few, even the devs, committing to have great tanks and healers.

Of course I know there are tank and healers of all different classes that are very good. But that takes truly learning your class is that specific role. There's no way I'd expect a new player to provide a great healer from a nightblade. Or a sorcerer tank. But they can sometimes do okay with dk and temps in that role. The game isn't really that difficult. But I suspect there's a huge learning curve in a trial that probably only the deaths of eleven other people can teach you.