What is the counterplay to bruisers and tanks as an adc or mage?

So heres the thing. You are playing a mid lane mage or an adc right? When all of a sudden a Darius or Garen walks up to you and Slows or silences you and then starts beating the crap out of you right? Well im sure this has happened to everyone, but what is the counterplay to a tank with 4k hp that can instantly fuck your day by building 0 or 1 damage item?

Lets say you have 5 damage items and a GA or idk a Deadmans on an adc. Then along comes 5 tank items with 1 damage item, and then they can instantly win that fight because they have more defense than you. How is it fair that someone with 3k hp and 200 MR and Armor can instantly beat an ADC in a fight because they have low defense from building offensively? At what point is base damage too high Riot? Its a little ridiculous that people are playing "Tank ____ Top lane" because if you cant die, you instantly win a fight. If an item like or is going to give you health, you can't make it also give them a shit ton of offensive stats too. As an adc, you have to prioritize damage items to be useful early, but when others can just build straight tank or bruiser early they will wreck your day in an early skirmish.

I think an easy way to make this more balanced would be to either add more early game hp or resist to ADC items or reduce the amount of damage increase on most tank items. Investing half the gold of an adc item into something like steracks that gives them essentially just as much damage and makes them even tankier is completely unfair to squishy carries.

Let me know what you think about this in the comments and if you think i'm wrong on any of this, then please give me your logic behind this because the idea of a tank beating an ADC or Mage in a fight SIMPLY because they can out-tank the others damage is uncomprehendable.

Thank you

Edit: Poppy + Iceborn + Full tank. You cant kill her because she has 4k hp and she will destroy you because of the high ass damage on sheen proc. Or Add a thornmail and you kill yourself while they take negative damage. Same concept of needing a premade team that isnt stupid right? Never fight the tanks, but let them free farm the game away is what every comment is saying :)

Edit #2: Here is some evidence from a recent game i played of a garen being unfuckingbelievable with only 1 damage item :)

https://gyazo.com/ba847f58f80022fad7cc5a8e796ef9f0 https://gyazo.com/b61f6d3c7a11cee667ae62ff12e809f1