My analysis is very different. I feel that nanotech will have a profound effect
as soon as the machinery is available, even if we are constrained to today's
computational levels for control. A single assembler arm operating under control
of a macro-scale computer should be able to build a logic fabrication factory
in a matter of a few weeks, even if it has to spend a portion of that time
building replacements for itself and doing testing and rework. Therefore,
I believe that given an assembler and one of today's desktop computers, It
should be possible to build a supercomputer factory on your desktop. Well over half
of the current cost of computer components reflects the cost of the fab lines, and
most of the rest reflects operating and materials costs.
IMO a similar approach can build any simple diamondoid macro-scale part, such as
window panes, bricks, pre-cut building lumber, many machine parts, etc.
For any increase in the capabilities of the control system you should expect
an increase in the achievable complexity of the result. If by "advanced nanotechnology"
you mean the abiltity to make things other than diamondoid, such as potatoes, then
I agree, we need something qualitatively advanced from the "robot factory" model.
However, the IMO the robot factory generating diamondoid parts is easily achievable in
the 2005-2015 timeframe. This technoligy is sufficient to completely obsolete all
current capital equipment. If the groundwork in AI based on massively parallel computing
is in place when the assember is developed, then the assembler-built superconputers will
also precipitate the singularity.