re: Heinlein and the future
The slidewalk still hasn't gotten beyond a limited run of "horizontal escalator"... though I could be wrong -- it's a long time since I was in an airport. Surely nothing like the tech behind "The Roads Must Roll".
On the other hand, Heinlein 'predicted' CAD... in "The Man Who Sold the Moon", if I recall. His automated drafting machine was a programmable X-Y bed plotter (with no indication of the programming interface... was it graphic, or pure Cartesian algebra?), but it was there, nevertheless.