Perhaps KiCad could assert a compilation copyright on the library as a whole, while releasing the individual symbols and footprints to the public domain.
Although personally, I’m not really concerned about Autodesk using the KiCad libraries. I think it’s unlikely that they would, and even if they did, I don’t think it would hurt KiCad any. I don’t think that “better libraries” is the reason why people choose KiCad over Eagle.
Exactly the same applies to PCBs designed using commercial packages. And you had better never read a manufacturers datasheet and derive a footprint from it.
This is why PCBs are defined as tools and not copyrighted in the West, otherwise nobody could do anything
The package dimensions, pin spacing, etc. in those datasheets are factual data, which is not copyright-able. However, the text and images in the datasheet may be.
Similarly, while the actual data in the libraries isn’t copyright-able, the library still is.
Depending on how the EDA application incorporates the data into the exported PDF/Gerber/etc files, at least 2 vectors for “leakage” of copyrighted material are possible:
If the EDA app copies strings of bytes from the libraries into the export files, then the export file could be considered derivatives of the libraries.
If the EDA app extracts the data then generates new byte strings to put in the export files, then the export files could be considered derivatives of the app itself.
Commercial EDA apps deal with these issues by stating, in their terms and conditions, that the designs are the property of the users, and that the files produced by the app may be distributed by the users (subject to any limitations accompanying third party libraries the users might choose to use).
The other step needed is for the KiCad application license to include a statement:
Any designs produced with KiCad are the property of the user.
Design files generated by KiCad may be distributed by the user who produced the design, subject to any limitations accompanying any third party libraries the user may choose to use.
(The above should be vetted by an actual intellectual property lawyer before incorporating in to KiCad’s license. I am only relaying the concerns presented to me by the people reviewing the business issues. (The engineering review ended with acceptance of KiCad.))
That is the theory in the USA and maybe Europe. All jurisdictions - who knows?
Simulation models are another story and libraries usually contain something like this
** You may not sell, loan, rent, lease, or license the SPICE Model, in whole, in
** part, or in modified form, to anyone outside Your company. You may modify this
** SPICE Model to suit Your specific applications, and You may make copies of this
** SPICE Model for use within Your company only.