Caitlin Flanagan has a nice essay in the latest Atlantic about Katie Couric, the Today Show, and Couric’s failure as the CBS Evening News anchor. Flanagan does a good job of explaining why the fluffy-unwatchable morning shows actually mean a lot to a lot of people, and why Couric was so perfect for that role (the piece is ostensibly a review of a part-hit-job Couric biography). But the best part is Flanagan’s tidy put-down of the evening news:
That Katie has bombed at CBS is a testament, not to the existence of a glass ceiling, but to the fact that real revolutions are so thoroughgoing that they don’t just provide a new answer, they change the very questions being asked. … No woman needs to storm the Bastille of nightly news, because the form has become irrelevant: Oprah has immeasurably more cultural, commercial, and political clout than Charles Gibson and Brian Williams, and no young person is ever going to make appointment TV out of a sober-minded 6:30 wrap-up of stories he or she already read online in the afternoon.
That CBS and Couric didn’t realize this — and that newspapers have wasted so much ink (also see: Dan Rather’s fall from grace, Tom Brokaw’s retirement, etc.) discussing an irrelevant institution that few under age, say 58, care about — is as devastating an indictment of the news media as any stock-price or circulation drop.
Korr Values 
Howard Kurtz’s recent book gives a lot of details regarding the observations you’ve made here, and especially focuses on how Brian Williams, Katie Couric, and Charles Gibson have each approached the challenge of succeeding in an outdated genre (and in a world with Internets).