How could Digital's collapse be so precipitous? It's because, in many ways, financial performance data is misleading. As you move up to the top of the market, you're getting rid of the less profitable products at the low end and adding business with more attractive margins at the high end. The rate of unit volume growth might be tapering off as you pursue these smaller markets, but your margins actually look better. So Wall Street rewards your stock price until you hit the ceiling.

The reason why it is so difficult for existing firms to capitalize on disruptive innovations is that their processes and their business model that make them good at the existing business actually make them bad at competing for the disruption. Companies in fact are specifically organized to under-invest in disruptive innovations! This is one reason why we often suggest that companies set up separate teams or groups to commercialize disruptive innovations. When disruptive innovations have to fight with other innovations for resources, they tend to lose out.

It's like in biological evolution: The population will evolve, even though individuals can't. The same thing happens in the corporate world: The population of business units within corporations evolves, even though individual business units can't. That's because the capabilities of business units reside in their processes and their values, and by their very nature, processes and values are inflexible and meant not to change.

How could Digital's collapse be so precipitous? It's because, in many ways, financial performance data is misleading. As you move up to the top of the market, you're getting rid of the less profitable products at the low end and adding business with more attractive margins at the high end. The rate of unit volume growth might be tapering off as you pursue these smaller markets, but your margins actually look better. So Wall Street rewards your stock price until you hit the ceiling.

Every disruptive innovation is powered by a simplifying technology, and then the technology has to get embedded in a different kind of a business model. The first two decades of digital computing were characterized by the huge mainframe computers that filled a whole room, and they had to be operated by PhD Computer Scientists. It took the engineers at IBM about four years to design these mainframe computers because there were no rules. It was an intuitive art and just by trial and error and experimentation they would evolve to a computer that worked.

A lot has been written about the Internet bust. From my point of view, it's quite clear the Internet isn't a category; the Internet is a technological infrastructure that can be deployed to facilitate a disruptive business model or a sustaining business model.

I was lucky enough to build on the work of a number of people who had already run laps around this theory-building track. The original classification scheme, years ago, distinguished radical from incremental change. The theory said that established firms managed incremental change well, but would be expected to founder when their industry encountered a radical change.