I realize this peaked with old hardware, but I wonder, do visual artists that want to use the latest hardware for similar art not count as part of the demoscene? Why not? I imagine these hackers liked the technical challenge but also the aesthetics.
It's trivial to "count" as part of the demoscene. Just release your work at one of the numerous parties held every year. All the smaller ones even accept remote entries. An important part of the culture is that the releases are non-commercial, free to distribute and so on.