"Rebadged Cheviys don't create legitimacy for a brand"

With you there, but not here:

"the G8 was a huge mistake and sold horribly."

The car, by itself, was awesome.

And while it wasn't a runaway sales success, it didn't really have enough time to permeate the market. However, it garnered enough "street cred" to be a halo car, which -- as you know -- doesn't need to sell in Cruze-like volumes to create interest in the brand and its other products.

Even then, the G8 was the flagship Pontiac vehicle, and -- when measures against other flagships -- like the current Ford Taurus or Hyundai Azera, it sold well.

But two good vehicles don't make up for a lineup-worth of crap.