Probably more to do with Holden's now being fully imported, so people don't see the difference between getting a VW and a re-baged Opel. Holden Australia had to beg GM to make a V6 version of the Opel that will be the next commodore.
You Aussies are so susceptible to jumping to conclusions, I came to Australia 8 years ago with nothing, now I have a home and 3 investment properties. I'm greatful to the country for supporting me and my large family in the first 4 years, but it seems Aussies would rather complain than work.