The business model for network television has been to use its monopoly of the distribution system to make money. That monopoly has been undercut repeatedly in the last twenty years. First cable, then satellites, now high speed internet.
With the arrival of an HD quality fiber line at most homes in America within the next ten years, the monopoly will be completely gone. Anybody who can afford server time will be able to be a programming provider. Servers, and thus server time will just keep getting cheaper. The nets will still have their brand names, but that’s about it.
Sadly, the loss of the income associated with the monopoly will also mean that budgets for shows will continue to decline. Look for an era when you have your choice of two thousands programs, almost all of which are low-budget reality shows. Think ‘nationwide public access channel’.
Then.... somewhere around the end of the next decade... somebody will come up with the idea of selling high quality programming on a pay-per-view basis, and a whole new era will begin.