"Geo models were manufactured by GM in joint ventures with three Japanese automakers. The Prizm was produced at the GM/Toyota joint-venture NUMMI assembly plant in Fremont, California, and the Metro and Tracker were produced at the GM/Suzuki joint-venture CAMI assembly plant in Ingersoll, Ontario. The exceptions, the Spectrum and Storm, were entirely manufactured by Isuzu in Japan. Geo Metro convertibles and early Geo Trackers were built by Suzuki in Japan."
Postscript: The NUMMI plant is now owned by Tesla.
Definitely not something unique to them, I just don't like that practice - also, you usually have the regular car brand and the upper-market version, e.g. Lexus/Toyota, not N degrees of "luxury" e.g. Audi/VW/Seat&Skoda. I like what BMW are doing, they have 3 branches based on different applications/philosophies.
How is this different from Honda/Acura, GM/Cadillac, or Toyota/Lexus?