I think they assume nobody ever changes the channel.
I watched CNN most of the evening - cuz I'm kind of weird and enjoyed watching them squirm. What I saw was that CNN was the first network to call states when Hillary won. They declared California for her about two seconds after the polls closed.
But when it went the other way, it was a very different story. They waited a good THREE HOURS beyond everyone else in declaring Utah. And at least ninety minutes on Florida.
You may have seen that I went to bed when my wife found Google calling Pennsylvania for Donald Trump. At that point, Trump had won the election. CNN took another hour to acknowledge the same thing.