It is a systemic issue. That's the point.
Removing incompetent people within the system, or idiotic judges, or overworked social workers who missed something and letting them take the fall might make people feel better and think "justice has been done". But it won't have been.
Of course people should be accountable for their decisions when they're responsible for child safeguarding, but it's a bit late by the time the child is dead.
And who will it help? Will it bring Sara back? Will it bring back the others, the list too sad to go through yet again. No, it won't. Will it stop this happening again? No, it won't. Because the entire basis upon which the decisions being made is wrong, so even if the protocols as they stand are followed properly children will still suffer and die. And these won't be the last incompetent judges or social workers who ever exist, realistically.
If people actually want this to change, want to not be reading about another child like Sara in 6 month's time, then the entire system must be changed. Children will continue to suffer and die like this until this happens.
The next Sara's process has already begun. In fact, there are hundreds of them, around the country, going through this right now. Just having got home from school to be welcomed by a beating, being burned, being locked in a cupboard, starved, humiliated, sexually abused, tortured. This is their reality, every day of their lives. And it will never change unless the voters of this country make clear to politicians that they will not vote for any party who does not fix this. It's barbaric, and it does not have to be like this.
It's all very well looking back afterwards about what went wrong and holding people to account (rightly) but the greatest service to Sara would be to look at what must be done now to stop others suffering to same hell of which he entirety of her short life consisted.