first of all i'm comparing both in their prime: favourable meta + equal or ahead.
Ever tried playing adc when behind? yes ADC have about 4 different stats that synergise, however they also need atleast 3 of those to do any damage. try and tell me just how hard your "Burst per Second" is now.
This is why i say "about the same damage" considering ADC have bigger dps timeframes because well they're ranged.
Adc often have some form of CC or peel or Mobility and will give up something in the other department (or not
). But most of the time it's not enough to stop an assassin/bruiser on their own. The only one i can think of that has Hard CC instantly is ashe and that's her ult.
However most bruisers in general have sticking power, High damage and slightly more burst than adc, atleast the modern ones.
Accompanied with some decent CC (not always ofcourse) and beefyness comparable to tanks. Illaoi/darius healing a shit ton of their health back isn't that rare either, Nasus has built in LS, Garen & mundo have health regen, etc.
And it's not as if they don't have tools to get near you, illaoi pretty much forces you to fight her, Mundo has perma slow, Nasus has 99% slow, Darius has pull, Garen has tenacity+MS steroid.
But in the end both need their team, Juggernaut's to bring the fight to them and adc to protect them.
Draintanks are problematic 90% of the time, AFAIK WW is the only succesfull one up until now. The only reason adc are able to do that right now is because shields are fucking broken rn.
If riot balanced to game to force Juggernauts to be the main carries then why would i ever want to be squishy? why would i want to be a mage if they can just stack mr, why would i want to be ADC if the tanky guys are better anyway, why would i want to be an assassin if the main dps won't even feel me burst him.
Both Classes have flaws but let's not forget the juggernaut update and the meta that followed.
EDIT:
Forgot to mention this.
Can we fucking stop with this BS "ever been X when behind" argument? Yes your champ is thrash when behind big surprise maybe it's because the enemy is ahead?