Defense fail to pick up key facts

Why did the defense fail to follow up on a key fact actually admitted by the Prosecution in their response to the direct appeal brief filed on Anthony's behalf, that:

"There was no evidence at the continuance hearing that Memphis and RD were certain to testify for the state in trial. Both men were unlikely state witnesses: RD was a co-defendent with a fifth Amendment right not to incriminate himself, whilst Memphis was appellant's nephew and a brother to co-defendent, Claude Nealy".