You have to remember that promoting the horse race is good for ratings. As long as the audience thinks it's a potential cliffhanger, they stay glued to the TV screens.
The media portrayed the 1980 election as too close to call right up till the moment Reagan crushed Carter.
They did the same thing in 2004, feeding false hopes to those of us who hoped the public would wake up and get rid of GW Bush. I had started watching electoral polls early on during that election too, and the pattern was much the same as with this one. Media portrayed the election as very, very close, always tossing out nationwide polls and nationwide indices on things like likability or preference on specific issues. No discussion of the electoral college at all. The reason was simple. Bush held the lead in electoral votes from the very beginning, and never gave it up. This year, Obama's lead is far greater then Bush's 2004 lead was, though.
In 2008, the media again portrayed the election as far closer than it actually turned out to be. The McCain campaign knew it too.
It's what they do. They want the ratings, and they want the advertising money that goes with them. Fox will see its ratings plunge by 25 to 30% after the election, as they did in 2008. The rest of them will see drops as well.