The reason is simply that while textual languages all use the same glyphs (ASCII characters), each visual language uses its own glyphs. Also, the design of vi

The reason is simply that while textual languages all use the same glyphs (ASCII characters), each visual language uses its own glyphs. Also, the design of visual languages hasn't reached the level of maturity textual languages have reached. When they have, sharing of editors might be possible to some extent. Until that happens, when you design and develop a new visual language, you also have to design an IDE, which makes it considerably harder than designing a new textual language. Perhaps VIM isn't also a programming language (I don't know how advanced its scripting language is), but EMACS has a built-in programming language (Lisp), and TECO, its precursor, actually was a programming language.