> Even a C64 or a ZX Spectrum would be a better choice than an RPi for teaching
This is the strangest opinion I've seen all day. My teen programming years were on a c64 in the late 80s, and in retrospect that was a really tough learning experience (and when I got to college and had access to 'anything else' I never looked back).
Also how was the c64 not a 'closed proprietary system'?