People that suggest "ramp up damage" for ADCs are extremely tilted and need your sympathy
The only thing suggesting "ramp up damage" does is let everyone know that you don't play adc. There's also a good chance your master strategy in game is making a B-line to the enemy adc, walking straight through their frontline, and you're supposed to win because you're a tank/assassin even though you're 3 levels down and have a 70 cs deficit.
"Ramp up damage" would kill the role and make it unfun. The whole game would have to be changed in order to make a mechanic this bad be viable. Crit functions exactly as "sustained damage over time" but math was never your strong suit so you don't understand why that is. As an experiment, try playing an adc with all zeal items and see how that goes.