My answer to this question is pretty basic: he already has. Is the Mariners farm system good? No. Yet it is good enough to accomplish it’s one and only goal: to make the big league team better. Remember, Modesto winning the Cal League means a lot to that team, but as Mariners fans, it’s nothing more than a neat story.
You care about winning here, in Seattle, above all else. So yes, Jerry Dipoto has dealt away some pretty good prospects. He gave up Luiz Gohara, MLB Pipelines #42 ranked prospect, and got nothing of value in return.