why are adcs harder to kill than tanks?

here, I got three examples here for you. Caitlyn. Early game she isnt too oppressive, but when late game comes, she can set 5 traps and cover the whole lane, forcing people to step on them and take a 2k damage auto attack to the face. she has 650 attack range I think, meaning she can kite for days. her traps have a very low cast time, she has her net to both slow you and give her a boost at the same time, and killing her is harder to do than killing a 5k health 300 armor and mr volibear with his passive up. Ezreal. Blue build specifically. He gets 40% cdr, or even 45%, and has a strong slow every 1.5 seconds at a large range. Hitting people with this long range spammable skillshot reduces the cooldowns of his other abilities, meaning his E can have a ridiculous up-time. I honestly have more trouble killing blue ez than I do killing the fed 6k health garen. Graves. lol lifesteal fucking hell, random ass tank stats for literally no reason, a dash that he can use while snared, thing has huge range and does stupid damage. Shouldnt adcs be easily killed when out of position? In one game as volibear, I couldnt kill the ezreal on the enemy team even though he was in the front lane 9 times out of 10.