They don't care if it fails. The networks' first priority is to get people to watch on TV. The brief ads on Hulu cannot support these big budget TV shows.
Hulu was created to deter people from downloading torrents. They make nowhere near as much money from Hulu viewers as live television viewers. But they realized that they would make no money at all if people downloaded torrents.
What incentive would they have to offer Hulu for free on a device that can't download torrents anyway? Not only that, with 3G models, the iPad is more convenient than TV. Instead of getting revenue from people that would otherwise pirate, they would now be losing real TV viewers, their real source of profit.
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