I'd say it comes down to two big issues: the first one being the tooling just isn't there, and people don't want to do this stuff in code. The second—and I'd sa

I'd say it comes down to two big issues: the first one being the tooling just isn't there, and people don't want to do this stuff in code. The second—and I'd say probably bigger—issue is that video streaming has solved the problem in most cases instead. Flash animation had its heyday when it was the only way to deliver video and games on the web realistically. With video streaming being so easy and having the added benefit of platforms with lots of eyes already, animation is a hard sell. As you say, responsiveness is a huge advantage for animation, but unfortunately I don't think that is enough to get people on-board.