I really believe we will be bypassing the networks and cable content providers and getting our content directly from the internet soon. When people get used to their DVR and understand these can be directly connected to an online program guide and online content the whole idea of TV schedules will go away. My ReplayTV (1999 technology) has the capability of sending and receiving content over the internet (one reason Sonic Blue was sued out of existence). All it will take is a content provider who wants to tap that market.
Some day soon there won't be "channels" or "time slots", only a catalog of shows.