That is really interesting. I wonder if there were any other interesting uses of paid programming to solve problems like these around that time?
A little less crazy and more straightforward (software on audio tape was super common after all): Radio stations and vinyl discs that transmitted programs to the microcomputers of the time (C64, TRS-80 etc.) have quite a long tradition. Some examples:
http://www.trs-80.org/basic-over-shortwave/ https://www.youtube.com/watch?v=6_CZpFqvDQo&t=2s