Hahn did not “inherit” one of the “worst farms in the system”. He was the #2 guy in charge within the organization for ten years prior to his promotion to GM and was primarily responsible, along with KW, for the state and condition of the farm system at that time.
And to date, many years later, he still hasn’t built a scouting and player development program that can achieve a top ten farm system status on its own and not rely on trading off major league assets to acquire other team’s top prospects to do so.