IMO your statement is partially incorrect. The GPL allows you to copy, modify, distribute the 'source' code and you can do all of them without the need to manufacture anything.
What the GPL states as well is the freedom to 'run' the program. Now if we want to continue with the parallelism hardware/software, than it would not be possible to 'run' the hardware unless you build it.
For the specific case treated in this thread, the assumption that the underlying hardware to run the IP is /accessible/ to the user is very similar to the assumption that a computer is accessible to the software user as well.
The copyright protects the 'original work of authorship', not necessarily the mean it comes with. And the license grants certain rights on the original work, not necessarily the physical mean.
You can easily grab a piece of the schematics and embedded it into your design, provided you distribute under GPL.
There are software that runs on cluster of computers and are licensed with GPL and is certainly legitimate to do so, I doubt that John Doe will have the capability to run the software 'as is' but he can certainly read it, modify it and distribute it.
GPL came to protect freedoms which are not at all linked to the cost of production. Yes you are free to produce a hardware artifact and this freedom does not contraddict any of the GPL statements. Whether it costs too much for you to produce is another story and has nothing to do with the license which remains valid.
Al