A big part of why ADC's are very strong is just support itemization
It's too good right now. It's easy to make an ADC unkillable with insane amounts of shielding, healing and whatnot. Support items are too cheap and too strong. Even toplaners start to take those. While I do understand that support has not always been a fun role and will always remember the times where supports in competitive barely had anything more than tier 1 boots when they needed to purchase green and pink wards back in the days, While I also respect support players a lot, This is unbalanced. I would rather have supports buffed and support itemization nerfed than an automatic ADC meta because it's too easy to make him immune to assassination. And I'm aware it might once again cause the problem of some supports going to sololane such as Lulu or whatever.
It's not like adc's are weak either. The powercreep has been both in the marksmen reworks and also in the numerous support item improvements; and it has drastically increased botlane influence, to the point where the game is way too dependent on botlane success.
that lets them be safer without any tradeoff. lets not forget they gave them scaling mr/lvl too.
and carries have always fucking had

, but any support can viably buy these items because their actives are so strong. So enchanters lose a unique characteristic to their kits. But at the same time, a lot of the support items make squishy supports needlessly tanky with all of the added survivability, armor, and mr. It would be equally crazy if Riot created an item which offered AOE hard CC.