To put in perspective, notebooks are how using the REPL on Lisp Machines and Xerox workstations (Interlisp-D, Mesa XDE, Mesa/Cedar, Smalltalk) feels like.

Those machines came and went a bit before my time, but I do recognize the sense of excitement and power I feel in notebooks in the recollections I’ve read.

Similarly, comments about ‘how do I distribute a Smalltalk program if it’s just the image of the entire VM’ rhyme just a bit to my ear with ‘how do I share my notebook with my coworker if it’s really the agglomerated state of my interpreter and language environment’

In terms of Smalltalk the answer is quite easy, you would trim down the image as kind of "release build" and ship it alongside a tiny executable that would load it.

No big deal other that talking rumors without reading manuals.

I didn't mean to imply that the answer to either question was 'can't be done', but that the analogy might extend to the the points of friction as well.

Sure, and my point was that mostly the friction in Smalltalk's case, was not reading the documentation and having an opinion without Smalltalk experience.