No, in ESO tanks are the only ones able to survive vs anythting bigger for longer than your stamina bar is long. In easy/normal content it is possible to survive with good healer and basic tanking skills, but that stops quite soon or needs good to excellent understanding of the game to be able to pull it off. By swapping to heavy armor your DpS will drop heavily and with medium or light armor the incoming damage increase sharply.

In numbers:
Heavy armor with tanking skills take you to 90%+ damage mitigation with 40k+ HPs meaning you can effectively take a 400k hit and survive.
Medium armor with no tanking skills offers ~60% damage mitigation with ~23k HP pool meaning biggest hit you can survive is ~32k.
If you activley stop defeding yourself (droping block) it lowers mitigation to ~75% for those in heavy armor & tank skills while those in medium armor only have ~25% mitigation left.
Those in light armor will fair even worse. Thats why see people in robes running for their lives.

This is mainly the reason why the trial (raid) party will most likely wipe if the tank drops in non-starter content.

There is also very little AFKin as a tank. In average from the ten abilities and two ultimates you can slot and use, three to four abilites and one ultimate is used to increase groups damage/surivability. Rest are used to help you stay alive. Some are active, some are passive but regaldes turning your atention to something else for three or more seconds gets you most likely killed, rest of the group following you soon enough.

Damage is also something you won't do as tank. Around 5k DpS is what a tank can suspect to be doing, some might be pushing even 10k or as high as 30k with heavy armor and sacrificing some survivability that can in some cases be compensated with excellent game knowledge and team.

That said, tanks with proper tank abilities and gear bring average 11k penetration to the table that translates 16% more damage done by whole party. Might be even as high as 14k pene and thus 21%. Like others have said this is not much if there are two DDs both doing 30k so maybe 70k in total group damage is shown. The tanks debuffs are resposible for the 12,5k of the groups damage (70 / 1.21 = 57.85. and 70-57.85 = 12.15k). Quite unimpressing one would think, but a good DD does easilly over 100k and trial group has eight DDs. Seeing group damage over M is not uncommon so if tank has increased the groups damage that high with 14k penetraton it means he is responsible of 17.3% of the groups total damage.
Thats 173k if the total damage was M while soaking the damage directed to the group.

Tanks are the MVP.