There is an interesting discussion on Slashdot about Moore's Law.
The gist of it is that even though Moore's predictions were originally based on a specific technology with physical limitations, companies have become so dependent on the revenues that come from the sale of faster systems and other add-ons that are based on these faster systems that they have a strong economic incentive to do the research and development necessary to maintain Moore's Law, even if the underlying technology on which it is based changes.
