And who will do so? Since there is no central authority managing bitcoins, I doubt anyone will be willing to do the advertisement with their own money. The money you'll be putting into the advertisements can be utilized in buying bitcoins so why go the other way?
The possibility is the exchange site because those who can get profit from the increasing number of bitcoin user is exchange site. but seeing the huge cost of advertising on television, I think it is unlikely exchange site want to advertise on television.