A key to its success was the way it blended its new and legacy businesses. While the library of material available for streaming was relatively sparse because of Hollywood licensing restrictions, Netflix customers could find many of those missing movies, especially new releases, in the company’s far larger DVD selection.

But Netflix needed to spend more money to license additional material for its streaming service. Collecting $10 a month from subscribers was insufficient as costs ballooned. Mr. Hastings defended the increase last week and again on Monday, but he said it was “too big a price change all at once.” Hubris played a big role in the errors, he said.

For well over a year, all the signs seemed to indicate to Netflix that customers were ready to move quickly to a future in which movies and TV shows would come to them instantly over the Internet instead of in the mail. Mr. Hastings said the decision to form Qwikster, as the mailed DVD company was to be called, had been based in part on data that showed a faster-than-anticipated increase in streaming by its customers.

In the first quarter of this year, for the first time, DVD shipments were down year over year, leading Netflix to declare that the DVD business had peaked. “Very few” new subscribers were choosing to get DVDs in the mail, Mr. Hastings said.

Stuart Skorman, a Bay Area entrepreneur who previously ran a chain of movie rental stores and an Internet movie venture, last year worked with Netflix managers after licensing to the company a database of movie recommendations. He said he was struck at that time by how little Netflix seemed to care about its DVD rental business.

“I think they should have been paying much more attention to it because that was their customer base,” he said. “That’s what made them special.”