Every successful foster child has a stable adult in their life != every foster child with a stable adult in their life is successful.
The first sentence is saying that a stable adult is one necessary component. The second sentence is saying that the stable adult is the only necessary component. They are totally different claims with very similar wording.
The first sentence is saying that a stable adult is one necessary component. The second sentence is saying that the stable adult is the only necessary component. They are totally different claims with very similar wording.