[2020] Tanks are the new bruisers and assassins

So i want to talk about tanks. In my definition, a "tank" should be able to tank damage. The problem starts, when a tank is able in same conditions of items and level to 1v1 any assassin, fighter, bruiser, mage... You take right now a malphite, ornn, mundo, zac with lets say lvl 11 and 2 items and let them fight 1v1 against any fighter, bruiser or mage and in about 90% of the matchups they will win. I understand that a tank need somehow to deal also damage. But at the end, a Tank should be a Tank. In my recent games i had often a Tank second in damage dealt while building only tank items. Just my 2 cents about the current situation of tanks

EDIT: I am not saying tanks should not be meta or viable. But in my personal definition of tank, a tank should be TANKING damage. Not dealing damage or beeing able to 1v1 any other class in SAME conditions. If riot wants champs do all be able to do the same, the simply remove classes like tanks bruiser marksmen etc etc and just call all of them "champs" and play the meta/map like you want. But if you make a class called TANKS, then they should be specialized in TANKING, not "outdamaging"