NBC is just the canary in the coal mine. A lot of forces are converging now and they're not healthy for the future of broadcast. All the networks face the same future, it's just that CBS has more padding and will be the last to go.
Younger viewers are using technology to opt out of the ad-supported ecosystem entirely by using DVRs, Netflix and of course piracy to timeshift their viewing and avoid watching ads. Comedy and drama is on the path towards House of Cards
Not only is broadcast losing the viewers advertisers want, they're losing advertisers because (big surprise) online advertising is increasingly more attractive to them.
No more Nielsens guessing game, now advertisers can get solid feedback on exactly how effective their ads are, and use that data to negotiate better deals. Online advertising puts more power in the advertisers' hands so of course they'll prefer it.
Broadcast will survive, but with the focus on live TV - news and competitions (sports, election coverage, and reality TV) - because they cannot be comfortably timeshifted.
More fun stuff:
Sharp growth in zero-TV households.
It ain't just NBC.
If fall is the television season's sink-or-swim deep end, then midseason is the kiddie pool. Fewer launches, lower ratings expectations and softer competition often pave the way for such slow-growing hits as Grey's Anatomy, The Office and, most recently, Scandal.
But nearly all of the 2012-13 midseason entries have drowned so far and, with the exception of Fox's renewed Kevin Bacon hit The Following, have done so in rather gruesome fashion.
And I'm sure the quality of the shows themselves does have something to do with falling ratings. Broadcast shows overall are just so bland, and the new pilots for next season are just more of the same. Broadcast needs to realize why The Walking Dead, Hatfields & McCoys
and The Vikings
are killing them...they aren't just the same old boring cop shows and sitcoms. The premises are distinctive enough that they grab attention as something exciting and new.
Even when you have something that could grab a following (apparently Zero Hour
was like that, given the unusual amount of howling over its cancellation),
if nobody is watching your network, they aren't seeing ads for new shows and don't know it exists. Launching on V-Day doesn't help matters either.