> The biggest downside of Racket is that you can't build up your environment incrementally the way you can with Common Lisp/Sly. When you change anything in your source you reload REPL state from scratch.

I think no Lisp is a "true" Lisp if it doesn't provide two critical components of the Lisp experience:

- Live Images

- REPL-driven development

That's why Clojure/Racket and even Scheme are Lisp-y but not a true Lisp. The only true Lisp languages I've found are CL and Janet.

Is this not ultimately a late-binding issue? Maybe I'm missing something, but I've absolutely been able to incrementally build up an environment without resetting using nrepl and Clojure

You are not a true LISP unless you use M-Expressions like the LISP 1.5 manual from the 1960s says. S-Expressions are inauthentic.