How long is a long view?

I recently took out The Art of the Long View: Planning for the Future in an Uncertain World, by Peter Schwartz (1996, Currency/Doubleday). Schwartz's ideas about scenario building and planning clearly have merit but I just came across a section that makes me realize that his idea of the 'long view' is really just the 'slightly-longer-then-before-view.' The section is the introduction to a chapter on building blocks for scenarios and the need to understand driving forces that influence outcomes in order to do effective planning.

Schwartz describes how temple priests in Egypt at the time of the pharaohs would look at the color of the water in the Nile river to divine what the yearly floods would be like. Different colors signified which tributary the water was coming from and the tributary determined whether it would be a dry year, a good year or a severe flood year. He points out that the rain is one driving force on the welfare of the Egyptians and their dependence on the Nile's flooding for growing crops is another.

However, then he says "Had the Egyptians had irrigation canals and fertilizer, they could have planted crops further out in the desert. They would not have had to worry about the river flow at all." How long a view is this?