In The Great Gatsby, why does Gatsby conduct parties in his house, but doesn’t participate in the parties?

Gatsby knows that Daisy lives directly across the bay from his own mansion. He can stand on his lawn at night and see the green light on the dock at Daisy's home. He throws wild and lavish parties, hoping that Daisy will wander in one evening and he can see her again. Gatsby doesn't invite people to his parties; they just come. Hundreds of people from East Egg, West Egg, and New York all come to Gatsby's parties to drink his liquor, eat his food, and dance to his music. After Gatsby does see Daisy again when Nick arranges a meeting, Gatsby stops giving parties altogether. He has no further need of them.