We have to remember that German and EU law is different than the US. The US trademark courts decided that the Strat, Tele and P-Bass are "generic" in the 2004 ruling.
In the US trademark takes *active* defense to control the trademark, see the Monster Cable fiasco where anything music related being advertised as "monster" as a descriptor was being sued by Monster Cable because they have to actively defend the Monster™ name.
Fender didnt do that for any body shapes and tried to retroactively trademark them in the early 2000s. Warmoth, Tom Anderson, John Suhr, and a bunch of others who are making parts for these counter sued and won on the basis of a lack of defense on the part of Fender for decades.
Also trademarks are different from trade-dress which is different from a copyright which is different from a patent. All are defended and used in different ways.
The lawsuits in the 70s against Ibanez and others making copies of Strats/Teles/LPs determined that the headstock is part of a trademark but that it must be distinguished from a certain distance. However, you cannot trademark the function of a 6 inline headstock only the non functional bottom half.
I am not a lawyer and this is not legal advice just a layman's understanding of how trademark law is partially handled in the US.