"I mean, if its that complicated for you to try to make use of GPL code
without actually making use of GPL code, why not stick to your proprietary
code and be done with it?"
This, unfortunately, is a live by the sword die by the sword sort of issue.
If by promoting and consenting to legal arguments for an expansive
definition of derived works, free software advocates indirectly persuade
the courts to adopt such a definition, interoperability between proprietary
and free software may become impaired to the point of irrevocable
marginalization of the free software community.
For example, Windows applications do not directly make "system calls" in
the Linux sense. *Every* Win32 application is dynamically linked with a
number of proprietary Microsoft dynamic libraries at runtime. So
regardless of any exceptions free software advocates might want to write
into their own license, the adoption by the courts of the dynamic linking
equals prohibited derived work argument would make running GPL software on
Windows boxes illegal without the consent of both Microsoft and *every*
contributor to existing GPL software packages.
In addition, given the dubious distinction between library and system call
interfaces, it could become illegal to run proprietary software on the same
Linux box with GPL software. If they are both loaded on the same storage
medium, they become a collective derived work, right? What about the the
device firmware or the BIOS? That surely is a necessary part of any modern
computer. Forget the software, what about the CPU design, or the printed
circuit board layouts. Or worse, the hardware and software design of all
devices that are part of the same physical network.
Do we really want a world where companies have to partition their
operations into a GPL-net and a proprietary net, and at a minimum run a
firewall so there can be no possible communication or interoperability
between them? Because that is the logic of where all these expansive
conceptions of derived works are heading - namely tying software and
hardware developers hands so that no system can ever be constructed without
the explicit permission of every producer of every component in the whole
system. The GPL will become a dead letter overnight.