In my experience nothing could be further from the truth. However, if all people are used to - and probably 98% of content available online is in three minute bursts - then this is what they will ask for. I remember a similar poll around a year ago that found only 17% of internet users had, or were interested in, using online video.
If you make long form available in the guise of sports events, films or even half hour programming people will view it if a) it's well produced and b) it's interesting to them.
As I remember one famous advertising executive once told me about research: "You ask people what they want and they tell you what they've got."