They would be a solution if almost all parents used them, but parents don't want to socially isolate their kids since a lot of "social" activity is now on social media. It's kind of a prisoner's dilemma.

There's not necessarily wrong. Despite the vapid and damaging nature of most popular online media, isolating a child from it might have even worse social consequences when their real-life peer groups discover that they're not on social media or that their parents have neutered their phone. Some kids would turn out fine after that. Others would be socially destroyed for life (maybe with the right therapy they could become well-adjusted, but high quality therapy is rare).

Parental controls are intentionally gimped. They do the bare minimum while providing more than enough wiggle room for a tech savvy teenager. To implement a robust parental control scheme you need network level filtration which isn't something the average parent will know anything about.

Are they a better solution? Yes

Do they work currently? Not really

Are they too complex for the avg joe to work out. Unfortunately yes. (Something about the smartest bears and the dumbest humans)