Demos on (probably emulated) old 8/16-bit micros wouldn't require a beefy rig, and that scene is still active.
If you want to actually earn a living, I can recommended embedded C programming. It's as low-level as demos, much more boring, but hey you get a paycheck. If you're good enough with C/ASM to write demos, the only other thing you need is introductory-level electronics. You _don't_ need to be an EE--a few courses in the local community college would probably do it.