A few years ago, 3-D was hailed as the next big thing in television, the logical successor to high definition. But viewers in the United States did not buy the hype, and now the eye-popping format is seen as an expensive flop.

That impression was cemented last week when ESPN, the nation’s largest sports network and an early adopter of 3-D technology, said it was turning off its three-year-old 3-D channel. A spokeswoman said the decision was “due to limited consumer adoption of 3-D services to the home.”

The news spurred debate about whether anyone would be left watching in 3-D soon, or whether anything would be available worth watching.

“Many in the industry have said over the last few years that if ESPN ever pulled the plug on 3-D TV, that would be the format’s final chapter,” Phillip Swann, the publisher of the industry Web site TVPredictions.com, wrote after ESPN’s announcement. “Today, it’s hard to deny that statement.”