No less an authority than Sam Donaldson, the television newsman notorious for bellowing hard questions at presidents, has concluded that it's time to blow taps over that most venerable of institutions, the network evening news. Beset by mounting competition, journalistic missteps, changing demographics and the departure of some long-term marquee personalities, the network evening news program is a shell of its former self - no longer attracting the devotion that made it, in the 1960s and '70s, America's dominant information source. "I think it's dead, sorry," Donaldson said during a panel discussion at the National Association of Broadcasters convention in...