Hence, the popularity of the Design for Manufacturing concept these days...
They'd be probably even more surprised to find that it'd cost 10k - 15k to make the tooling.
Diagnosing / 'debugging' issues with injection molding is incredibly difficult - again - it's almost black magic, and it's sadly a skill that's getting harder and harder to find.
If you cast your eyes around your desk / room, we see molded plastic parts every where - so we make the assumption that they must be cheap and easy to do.
And indeed - the assumption of facility due to availability is a very common trap that many kickstart projects fall into.
It's harder to scaffold and pivot in real life ;)
ftp://ftp.cray.com/announcements/product/OLD/Moldflow_Partnership.930408.txt
http://www.clock.org/~fair/computers/sgi-cray.html
The latter should be authoritative, Eric Fair was an Apple sysadmin in the '80s or thereabouts (and son of the Fair in Fair Issac, the inventors of credit scoring).
And there were quite a few more links I didn't check out.
Extra funny if that exchange between Scully and Cray happened. One of computing's more interesting synchronicities. :)
Btw, I recently found out that Cray had another company making a play in reconfigurable market. He died in a car accident but they followed through with interesting technology:
5kUSD would be a conservative price from our factories; but the item is rather simplistic. As a general rule of thumb, for cases in plastic injection molding, you're correct - you're looking at 10 - 20k easily. Multiple pieces with complicated gating, the price goes up.
Zinc / Metal injection molding involves much more black magic, and this is reflected in the costs.
With all of that said - we're in complete agreement on the main subject - even if tooling cost 5k + 20c per piece, the estimation of $1 for PCBA + PCB Stenciling + molding is way off track, unless it was amortised over tens / hundreds of thousands of pieces.
Outside of the obvious external costs (development, transport, overheads, import, profit, etc), PCB + Tooling costs are often wildly underestimated.
For reference, a PCB of this size requires a setup + stencil template, which would run ~ 400 - 500 USD.
Tooling for the plastic injection mold for this piece would run around 5000 USD, and each subsequent piece would probably cost around 10 - 50c USD.
Tooling + PCBA done right have significant upfront costs that often seem to be forgotten.