Joost failure had nothing to do with technology. Instead they fundamentally misunderstood movie business and had a wrong business model. They did solve half of the problem, cost of bandwidth, but they failed to solve the much harder half — upfront cost of content.
The story goes is that Joost came to studios with $40 mil to get rights to movies. They were told that that a prime movie rights were $10 mil prepay upfront, so they could choose 4 good movies, or a large library of junk. They chose junk, but neither option was viable.
To do business the way they wanted to, Joost was undercapitalized by a factor of 100.
YouTube and Hulu solved content problem differently. One through copyright infringement, the other though being owned by content owners.