Except the original Lisp and Smalltalk environments are much more than a simple REPL.
Sometimes I wish people would learn about computing history.
Presentation from Kalman Reti about Lisp Machines, check the interactivity starting at 00:44:00 and how to introduce mouse sensitive images at 01:00:00
For me "more-than-REPL" just looks like a code visualization tool where you can jump between symbolics. Mouse sensitive images looks just like a prototype of AutoCAD
Bret Victor's work is much, much more impressive, you can change variable values and see results in realtime. In that Mario game example, you can see Mario's trajectory and adjust values to see how physical parameters affect the height and distance Mario can jump, and modify gravity ticking equation to see Mario jump & walking up-side-down.
You could do that on a Lisp Machine, too. Symbolics sold a complete interactive animation and game development system. Nintendo used it in the early years. The software later got ported.
Parent really thinks Smalltalk had the capabilities, realized or not, to do the demos that Bret did in Inventing on Principle. Smalltalk and Lisp have never shown the capability, and in fact just can't do it. Time travel was just never a big thing there.
The Smalltalkers do this all the time; I had even Ralph Johnson poo hoo my 2007 live programming talk. But you get the feeling that these people really think nothing new can be invented after the 80s. They say "Smalltalk" already does this! And you say "show me" and then they just shut up.
All the ideas presented in Christopher Hancock's 2003 dissertation on live programming are compared adequately against previous work. There are plenty of advocates out there for anything that don't do their homework and don't bother with related/previous work sections...only academics like us concern ourselves with that.
Rediscovering Lisp and Smalltalk interactive environments.