I don't think popcorn is part of it to be honest. It's some adjacent siderail of groups like Mannheim Steamroller or BBC Radiophonic (eg Delia Derbyshire/Dr Who theme) or for that matter, video game music.

Check out the "Soothing Sounds for Baby" album by Raymond Scott (1962) for an early example of this.

To put Popcorn in comparison to what would be on the techno track at that time, look at Hugo Montenegro's Moog album, released the same year. His MacArthur Park rendition I would argue is a closer direct ancestor to techno being in the pursuit of electronic dance. Direct link https://youtu.be/eNM6187cznE

There's certainly "bridges" between the worlds like the 1979 Automat album https://youtu.be/w7nQHBiv_u0 or the Droids "Star Peace" but synth and techno are kinda like the catholics and eastern orthodox, they split off a long time ago and kinda have their own worlds.

yeah, now that you put some context around it, I understand I was a bit off. Thx :-)

To be fair, it'd need to be a book to cover everything and they include quite a lot here.