Regarding the Apollo and high-end technology discussion: It may be also interesting to consider the lower end, top-down dynamic. In 1976/77 IBM was working on various home computer concepts, and I guess, if any of these had become reality, we may recognize one or the other element of the 5100 in them. (The Aquarius project seems to have come pretty far with production prototypes and a concept for a software ecosystem, but was canceled over doubts of the real-world viability of bubble memory.) Had any of this happened, we may regard the 5100 as an important intermediary step in scaling down mainframe technology and bringing it to the masses.
PS: I’d really love to see someone with access to the IBM archives coming forward with something like “The untold story of IBM’s struggle for the home computer.”
On the speculative side, this may provide a reason for IBM being so secretive on the PALM technology, as this may have played a role in protecting a closed software ecosystem.