Moore's law is a rule of thumb, not a law of nature. There have been other
periods of exponential growth in technological capacity, and they all came
to an end, usually without anyone realizing in advance that they were about
to.
Commercial air transport improved from 1903 to 1970 at an exponential clip,
and has made essentially no progress since. Nobody had any idea in 1970
that progress was over. If we were still on that curve, we'd have
commercial trips to the moon. The movie '2001' was a plausible
extrapolation at the time.
What makes me confident that AI-level processing power is possible is that
(a) nature does it, and (b) Drexler has provided a carefully-worked analysis
of how it could be built. The timing could be either faster or slower than
Moore's law suggests. I would not be terribly surprised if economically
feasible semiconductor technology were to bog down after one or two more
chip generations. The maximum speed of a Pentium might be 500 MHz for
decades, until someone develops a breakthrough technology.
--CarlF
PS. You know, I seem to be the gloomy gus on this list, always pointing out
problems with other people's posts and carping about limits. In any other
group, I come across as a raving technological optimist.