My favorite Heinlein short story is "The Roads Must Roll". Why? Because his job as a science fiction author was to preview the future, and he missed something really big.
The "roads" are a huge solar-powered network of conveyor belts that have replaced all car, truck and train traffic in the US. Restaurants (among other businesses) are built on the roads so you can eat while you travel.
So far so good.
The main character is the chief engineer of the roads. How important was he? So important that whenever he ate on the road, the waitress always brought a phone over to his table and plugged it in just in case his office wanted to call him.