I think the conditions of the demoscene arising were a software interface that consisted of coding, and people's first experience with a computer was
10 PRINT "HELLO WORLD!"
20 GOTO 10
RUN
This piqued the interest of curious youth, who then were further enabled by a hardware interface where you could write a value into an area of memory, which would then appear as a pixel on screen.
Exactly this. Whenever I talk about how I got started in computer art over 40 years ago, I always mention the fact that a screen back then was a one-way device: TV network to you. Basic home computers HAD to plug into the TV, and to a kid, this was magic and freedom.