This is a quite inaccurate comment. The catalysts (in 1966) for the ideas I had included Sketchpad (especially), Simula I (a few days later), the ARPAnet (under discussion), operating systems inter-process communications (especially Project Genie), the Burroughs B5000, my old biology and mathematics majors. All these are mentioned in "The Early History of Smalltalk" that I wrote for the ACM History of Programming Languages"

Actors appeared after I gave a talk at MIT about the very first Smalltalk.

There were several later ideas that were discussed at Parc but not taken up because of the whirl that was already going on. One of these was derived from McCarthy's "fluents" and "situations" (essentially a labeled states/layers idea for allowing concurrencies without race conditions -- this was done very well in David Reed's 1978 MIT thesis.

Another was not waiting for replies. This was in the original set of ideas -- via biology and OS techniques -- but never got implemented in a deep way. The hardware we had at Parc was tiny and Smalltalk was expressive enough to fit a lot into a little.

Another set of ideas that were completely missed appeared in LINDA by Gelernter. This (and the larger ideas around it) are very good ways to deal with larger scalings, etc.