It's a PA-specific nuance.  As revoltdx said, the state owns the stores.  It's a legacy rule from prohobition.  We all detest it, but there are some very power entrenched people who won't allow change.  This includes a very power union.  The situation has lightened up in recent years, and they will now allow wine to be shipped in from out of state.  Its still ridiculous and i refuse to shop at a state store...I go to Delaware.