The reality of things as I came to understand them were these; Jef Raskin was passionate about user interface design like few people I have ever known. The folks at PARC were excited about the possibilities offered by the advanced state of the art in graphics and input devices and they had some really excellent thinkers and engineers who were implementing really different ways of interacting with computers. Steve Jobs was passionate about design with strong opinions on what was "right" and what was "wrong" about any given product feature.

Now you have to put that into an engineering context. Apple is building a new computer system, one of its, if not THE, lead designers has ideas about how the user will interact with it. The company is pushing back on these ideas because they are "radical and new" and questioning how the engineers know that this will be a better way to build computers than the existing examples in the Apple II and CP/M machines of the day. So this conversation within Apple gets more and more energetic. If you are in an engineering company and are leading any sort of project you will have this experience. You propose something different than what the company expects, and the company pushes back on that proposal in a bunch of different ways. In an effect that is oddly reminiscent of how a band-gap forms in a PN junction, groups line up for or against the concept. And it percolates up the management chain until someone in authority "decides" and shuts down all of the side conversations.

Having had conversations with various people both on the Xerox side and the Apple side who were part of that experience, I concluded that Steve Job's visit to PARC where he saw a realized example of what Jef was trying to push through, convinced Steve that it was better design. I based that conclusion on stories about how the conversation within Apple changed once Steve had seen for himself the possibilities presented by a window based system with a pointing device. Jef related in a talk that he gave about interface design that resistance to the ideas essentially evaporated once Steve was on board.

So is that the "real" story? I don't know. It is the most likely explanation of events that followed all of the statements I heard from people who participated in the design of the Macintosh/Lisa and people who build XDE and Star (the Xerox Development Environment and their office suite). Does it matter? I don't know that it does, the origin story for the Macintosh is what it is.