Actually Bandai did make them ... for the re-issues, that is. Bandai made several "new" head sculpts in the 1/55 tradition for the re-ssiue Macross Valkyrie line several years ago, but unfortunatley the new sculpts only made it as far as the prototype stage.
New 1/55 heads & paint schemes were made for:
VF-1A Max (DYRL Blue)
VF-1A Hikaru (DYRL Red)
VF-1A Cannon Fodder (Brown)
VF-1J Hikaru (TV Series Grey)
VF-1S Roy (DYRL Yellow)
VF-1S Hikaru (DYRL Red)
VF-1D (TV Series)
There are @ 3 prototypes of each style valkyrie known to exist.
There were even new "new" prototype sculpts for the TV & DYRL pilots; as well as an incomplete sculpt for a 1/55 scale "Tomahawk;" roughly about 80% finished.
Rumor also has it that there was even a 20" SDF-1 prototyped, but no images have ever been seen. The prototype is still believed to be at the Bandai studio.
The re-issue line did not do as well as Bandai had hoped, due to fierce competition from Yamato & Toynami releasing thier toys, so it therefore lived a short life. Bandai did not think the retail price of new sculpts justified the mold costs. Perhaps in another few years Bandai may release the line again; but there are no current plans to re-release 1/55 toys such as the Strike, Elintseeker, or Super Ostrich from Bandai.