well... not a TOTAL vacuum. a number of the PARC people (thinking of Tesler & Kay) were intimately familiar with Englebart's work at SRI. When the ARC (Engelbar

well... not a TOTAL vacuum. a number of the PARC people (thinking of Tesler & Kay) were intimately familiar with Englebart's work at SRI. When the ARC (Engelbart's Augmentation Research Center at SRI) was winding down and PARC was staffing up, the people who left first were supposedly those who rejected the "brittleness" of the expert-focused software ARC developed. It's definitely true that the cost of implementing a frame buffer fell well into the affordable range as they were moving to PARC. And politics at PARC made it easy to say you were developing a system for "inexpert document managers." They were definitely exploring new ideas about HCI as PC hardware was emerging. But Larry Tessler was pretty clear that Lisa learned what not to do from looking at the Alto & Star. And the Alto & Star learned what not to do by looking at various bits of ARC software. And Engelbart was adamant his team not repeat the UI/UX mistakes of ITS. So sure... they were trailblazers, but they had a good idea of where they wanted to go.