Chelsea Brown

Chelsea Brown died aged two-and-a-half in 1999

The death of Chelsea Brown again called into question the intervention of social services in cases where children are known to be at risk.

Father Robert Brown was given a life sentence for what police have described as one of the "worst cases of child abuse they have ever seen". The two-year-old had been tortured and shaken to death by a father who had a history of violence towards children.
Derbyshire's director of social services, Bruce Buckley, acknowledged that his staff made errors in the case. "The workers were concerned and that is why they were visiting regularly but clearly on this occasion we did not make the right decisions," he said. There were Warnings Chelsea was considered at risk from her father as soon as she was born, and she was immediately put on the child protection register. But despite visiting the family at least 27 times in just over three months, the authorities decided it was safe to leave her with her father and mother Maria Brown, of Kirk Hallam, Derbyshire.
Neighbours said they warned social services that Chelsea was at risk after hearing Brown's outbursts of temper and the child's crying. Stephen Baker (a neigbour) said "The only retort we got was 'if you hear anything again give us another ring' and that was as far as it went." Another neighbour Bob Kemp said: "Someone should have picked up on it, end of story. To me it was totally preventable."
Even after a doctor suspected abuse when she noted bruises on Chelsea, the child was still not removed from her parents' care. Just over three weeks later Chelsea was dead after she was violently shaken by her father. Brown had a string of convictions, including actual bodily harm for slapping his 16-month-old nephew and another when he dragged him through the street. In February 1998 he was placed on probation for threatening to kill his own mother and a social worker. Despite his violent background, Derbyshire social services decided to allow Chelsea to return to her parents after her paternal grandmother said she could no longer care for the girl. "At the time Chelsea went back no-one could have predicted the outcome based on Mr Brown's previous behaviour," said Mr Buckley.
The couple by then had another daughter, 17-month-old Courtney, who Brown tried to blame for causing some of the injuries to Chelsea. Hilary Owen, the author of an independent report into the case, told a press conference that Brown had been able to mislead professionals about the cause of many of Chelsea's injuries. She added: "There was increased concern about Chelsea in the time she was living with her parents and removal was an active consideration in the last few weeks of her life."
Mr Buckley refused to discuss whether the principal social worker in the case, Norma McDevitt, would be disciplined.

Authorities agreed in 2000 that the many lessons learnt from the loss of Chelsea Brown and Victoria Climbie should this time guarantee that no child dies in such tragic and violent circumstances again.

My question
So why "authorites" have many more children died similar deaths since?

To sum up:

Chelsea Brown, two, was battered to death by her father. Robert Brown, who was jailed for life for her murder, had a criminal record for violence against children. Her mother, Maria Brown, was jailed for 18 months for child cruelty. The girl's social worker, Norma McDevitt, visited the family 27 times in the 10 weeks before her death. She took Chelsea to a paediatrician who said that six out of nine areas of bruising "had no plausible explanation" and at least one was deliberately inflicted. These findings should have triggered police involvement and a multi-agency case conference under Derbyshire county council's procedures, but neither happened