People say that tanks deal a lot of damage, which is a lie
Tanks actually deal little damage. At least when compared to a bruiser, mage or assassin, their damage is very small. Combine with the fact that they aren't going to build AP/AD/penetration, and their damage, which is already small, fall off very hard.
What peharps is happening is that people are using squishy champions. When you are squishy, even that small amount of damage is enough to kill you. After all, tanks have good base damage. Their lack of magic penetration doesn't matter if you don't have magic resistance (most tanks deal magic damage with their abilities) as then they can chunk off a large amount of your HP.
Investing in an early
,
,
, or even
, can make trading against tanks much easier, and can make surviving against them during a fight easier too.
Don't forget that most tanks need to come close to deal damage, too. As such if you are a mage/ADC, it is extremely important to kite the tank, otherwise it doesn't matter if you have magic resistance against them.
On a side note, for ADCs: if you are taking damage from their
, this probably means that they invested very early in that item. Thus, the tank doesn't have a lot of HP and/or magic resistance. As such, your mage can deal huge amounts of damage to them. After all, Thornmail is ridiculously good against ADCs, but completely useless against AP mages.


stfu pls ty

and
on
or
. You'll have tons of kite and take very little damage. You also won't do a whole lot of damage, and don't bring CC or any other utility, so you can just be ignored in fights until the rest of the team is killed. I'd argue in that case the character is tanky, but not a tank, because they cannot actually tank for their team since there is no legitimate reason to damage them.