Risk vs reward for ranged carries vs melee assassins

What is the Risk of a Ranged champion building lethality? What is the reward of a melee assassin building lethality?

Here, im going to make this as simple as possible.

Risk: absolutely zero risks Reward: presses a single button and gets pentas, proceeds to carry the game with more R button presses

shadow form Risk: has zero sustain, so there is a HIGH possibility he will get blown up and killed while attempting to kill target. Reward: best case scenario he kills someone and gets out, good job.

this argument can be said for any ranged ADC vs a melee assassin. the two above me is just 1 example of many. ADCs need to stop stepping on a assassins shoes.