If the networks chose to air Obama's entire speech live, instead of taping it and airing it after Clinton was finished, that's the decision of the networks. I fully agree with not expecting (or even encouraging) people to stay up late to hear you talk. Besides, I'm sure both candidates realize that each speech will be all over the internet within a few hours for people to hear at their leisure.
If I were the second person to start, I'd consider waiting a reasonable amount of time to talk, as a nod to courtesy and tradition, but I wouldn't feel it was required. Technology makes it possible for networks to air the speeches back to back, even if they don't occur that way. Obama is not responsible for the reaction of the news media. They had a choice in how they used their air time.
I'd also be prepared to deal with only the second half of my speech being aired if I chose not to wait. *shrug* It's an understandable possibility and wouldn't be a big deal. The best of most speeches is the second half, anyway. Obama choosing not to wait could have cost him as much air time as it cost Clinton. He took the gamble. Again, the news media had the choice of what the people would see live.
