I think the problem is that social workers know there are very limited foster care homes or facilities - and if they work to get a child removed from the home there isn't anywhere for them to go. And the next house they come to do to a home visit the kids may be worse and in more need of those scarce resources. And many foster care homes are worse than family homes, so you get this hopeless feeling that unless the child's home is life-threatening it's best to leave them there. And then, the social worker has to make the determination on little information whether it's life-threatening. It becomes an incredibly depressing, and hopeless cycle for CPS.
It's easy to blame social workers, or CPS in general, but they can't create foster care families out of nowhere. They have to deal with the families that are willing to foster children, and there is a campaign recently to recruit more foster families. They work with what they have.
The real solution, IMHO, is not to blame CPS, but to somehow recruit more foster homes and homes like Texas Baptist Children's Home that's staffed with caring trained adults.