Randjack, the FCC and media industry is determined to shut down analog television so they can peddle HDTV complete with copy restrictions and the broadcast flag, so they can stop from recording off the air with VCR's. It's a gradual phase-in. First they require all new TV's sold to have digital capability. Then when 85% of the households have TV sets that can receive digital signals, they can shut off the analog system.

http://en.wikipedia.org/wiki/All_Channels_Act