OK, I'll try (fools rush in where experts fear to tread..)
Yes, strict economic theory can says that you can assign a cost to
anything.
This is almost a premise of the discipline. However, MNT is very likely
to make the cost of local production of almost anything, lower than the
transportation cost of that same item from a central site. That is, the
differentials in production efficiencies that drive the current economy
will disappear. With MNT, all I need to produce an item is the design
for the
item, and matter, and energy. This means that any individual who so
desires can
drop out of the global economy and revert to a "subsistence lifestyle"
with
material self-sufficiency. That lifestyle will be very lavish by today's
standards. I suppose that an economy in these three inputs (design info,
matter,
energy) could in principle emerge, but not in time to avoid a complete
meltdown
of the existing economy. It may appear that a trade in designs would
emerge, but
I strongly suspect that the designs needed for lavish self-sufficiency
will become
freely available. The matter will be literally dirt-cheap, and solar
energy will
suffice for a lavish lifestyle, given a very modest improvement in
collection
efficiencies based on MNT-built-and-maintained collectors. Anyone who
need more
energy can build a thermal tap, or a fusion plant.
Once MNT is available in crude form, MNT is likely to enable us to
"bootstrap"
very quickly to sophisticated MNT. At that point, there is nothing
material that
people currently need that a person cannot make. This means:
no energy industry.
no transportation industry (for goods.)
no contruction industry.
no maunfacturing industry.
no agriculture.
The bulk of the service and information industries (banking, etc.) exist
to support
commerce, and will also be rendered unnecessary.
The above can all be accomplished using MNT to simply build items
equivalent to the
ones we already have. There is no need to take advantage of MNT's
abiltities to make
new kinds of items.
There remains the personal service portion of the economy, including
medicine. My
crystal ball is cloudier in this area. It's not clear how we'll
compensate a provider
of personal service, unless each of us becomes a provider and can pay in
kind. Clearly,
there will be very strong inducement to automate these jobs, since MNT
implies that
automation is of near-zero cost once designed. I suspect that most
"menial" service
jobs will disappear immediately: houses and clothes will be
self-cleaning and
self-repairing, and any item can be replaced (completely recycled) to
renew or
repair it. Food can be created already-cooked, on plates, on the table.
Information services, such as teaching, are another matter. A great many
people
are likely to opt to teach their own children, assuming that instruction
in the future
looks like it does today. If computer-augmented intelligence develops in
this
time-frame, prediction becomes impossible.
Direct personal services for the human body, (medicine, etc.) are also
another matter.
MNT-based may of course help solve many of body-related problems.
Alternatively,
the difficulty of attending to a body may be an inducement to just get
rid of the
thing by switching to an MNT-built body.