The lost art of buying defensive items on ADCs

This is a follow up,for my earlier post that got almost 60 comments on it and over 7k views.

I've noticed some people insist that you should always buy only offensive items since they synergize well and if you don't the enemy ADC will out dps you and you will lose,and that it was always like that. But besides the obvious fact that an ADC isn't always the one that carries the game or the only damage dealer in the team,yes,i know,your mid,top,jg or even support (Brand,Zyra) can also do boatloads of damage and carry the game,i also got reminded by some people commentating about some old core items like pre-rework that used to give 450 hp,55 mr,spellshield and this * Grants +45 health regen per 5 seconds for up to 10 seconds after taking damage from an enemy champion or when the spell shield breaks. *

And i remember building it every damn game almost,sometimes as your last item sometimes as your 4th item,so i decided to check some old videos of season 3 gameplay and this is what ive found https://www.youtube.com/watch?v=BVENm6Paehw https://www.youtube.com/watch?v=CJ8FssofmtM https://www.youtube.com/watch?v=rhfO5-HVOVA https://www.youtube.com/watch?v=gljxkWbYGXM

Omen,Banshee,GA were all built pretty regularly,GA was more popular in pro plays as i can see,kinda makes sense since it was more organized play.

I just want to put the "X team will win over Y team cause their ADC has more DPS" argument to rest,i mean if that was the case why did we see Ninja tabi become a standard buy for ADCs not too long ago,why would anyone build GA instead of another damage item if they dont expect to take damage and die even in pro play,why would people get Merc scimitar over something that could potentially bring more DPS to the table,why did ADCs abuse Sterak so much that it got a melee only tag,why do people buy Maw etc.

Not every fight will play out perfectly,especially in anything lower than Diamond,its likely your team wont peel for you,your support will miss his hooks,stuns,roots,or will play Brand,Pyke,Lux and be almost completely unable to stop someone from diving you,or you will get poked half a screen away by or deleted before your supp can react by . In these situations going just one as your 4th,5th or last item does make a world of difference.

I just want to ask some of the older players,does anyone remember buying stuff like Omen,Banshee,even Warmongs during seasons 1-5? When did we start thinking that ADCs don't need that anymore,was it when supports started getting stronger?