Sounds like the people you describe were outliers with some preexisting conditions, and probably shouldn't be used as any sort of baseline or point of comparison.
Combination of abuse and unfettered access to drinks/drugs/Internet is way worse than either one alone. At the same time I think the issue of bad parenting is a) not one people talk about out loud because of stigma (we can attack tech CEOs all day for pushing addictive products but anyone can become a parent and none of them will stand to be called the "bad" one) and b) not amenable to much change save for a global in-house surveillance panopticon. Yes we can choose to place trust in parents to protect children from Instagram and PornHub, but consider that some parents just... won't. Neither can we force them to. What then?