Invaders from Unexpected Fronts

Again from Profit from The Core by Chris Zook:

The discovery of new uninhabited market territory frequently brings invaders from unexpected directions. Consider the following:

• Kodak's pursuit of the digital camera market encounters unfamilar competitors Hewlett-Packard and Canon.
• Quaker Oat's attempt to expand Snapple beverages run directly into new drink initiatives of Coca-Cola, with its unassailable distribution infrastructure.
• Xerox's entry into low-end copiers gets a surprise attack from Canon, an unconventional competitor the giant had underestimated.