Well, Mattel used Forth: https://groups.google.com/d/msg/comp.lang.forth/omi6PUvymEE/...

Because it was cheap: https://groups.google.com/d/msg/comp.lang.forth/LzOasFOyIMg/... (forth not mentioned here; plausibly(?) extrapolating)

Some nearby discussion about 6502 market penetration (I can't determine whether Forth is being discussed here - oh and dodge the cartoon fistfight-cloud wending its way between the posts, happens a lot on this usenet group): https://groups.google.com/d/msg/comp.lang.forth/Yoa9u55cpbo/...