Old 8 bits "family/home computers" were designed with teens and kids in mind - perhaps an influence of Alan Kay? BASIC means "Beginner's All-purpose Symbolic Instruction Code", so it was a good fit. The Amstrad CPC 6128 also came with a Logo implementation [1], which was an educational dialect of Lisp (I still remember how its associative lists blew my mind as a kid), on a separate disc.

Also, at that time "open source" wasn't really a thing, compilers/interpreters for various languages were professional, commercial tools [2].

[1] https://en.wikipedia.org/wiki/Amstrad_CPC#Other_languages [2] https://en.wikipedia.org/wiki/An_Open_Letter_to_Hobbyists