At this point I think he knows that the Salamancas are essentially a dead group of street thugs. He sees Fring as the future as a quiet big earner. It is easy to dismiss Salamanca at this point from the power structure.And why wouldn't Don Eladio believe Hector? Hector is an original, he literally came with no evidence and said the accusations knowing full well he couldn't back any of it up, and still did so anyways.