From what I understand, broadcast television never recovered from the blow it was dealt by the 1988 writer's strike; once viewers had found other outlets, many stuck with their newfound friends. Now it seems that this may be happening again:

Just because your favorite dramas and comedies are back on the air after the writers strike doesn't mean you're necessarily watching them. A preliminary look at ratings of returning programs on the big broadcast networks reveals that the "majority of original programming has failed to return to its pre-strike levels among key demos," according to Havas media-buying shop MPG.

The firm found that audiences are "coming back to some of the shows, but not most of them," said Nina Kanter, VP-director of communications analysis at MPG.

I feel like I used to mark off some of my week by television schedules--if it was Wednesday, that meant there would be an episode of House on the TiVo. Now that's pretty much fallen away. Nor can I say I particularly miss it, between Netflix, books, the internet, and the Wii. Most of the people I've talked to seem to feel the same way. It's early to tell yet, but I wouldn't be surprised if ratings took an even deeper dive this time around.