IMO, It's an obstacle only to people who don't use IDEs.
Someone who uses e.g. visual studio for C++ isn't going to balk at the suggestion of installing IntelliJ for Java, and I doubt that they would balk at the suggestion of installing SLIME for lisp.
In my experience it's people who live in their editor (sublime, vim, &c.) that balk at the idea of installing an IDE as the first step for using a new language.
It might be annoying but it probably wouldn't be an "obstacle", especially considering things like evil-mode exist.
That's how it went for me, anyways. From vim user to trying Emacs because it has some feature that I need to becoming a full-time Emacs users with evil-mode
Someone who uses e.g. visual studio for C++ isn't going to balk at the suggestion of installing IntelliJ for Java, and I doubt that they would balk at the suggestion of installing SLIME for lisp.
In my experience it's people who live in their editor (sublime, vim, &c.) that balk at the idea of installing an IDE as the first step for using a new language.