To understand why the Lexus GS didn't sell well in Europe, you have to understand the European market. No Japanese brand does well in Europe and this is why no Japanese brand really targets Europe heavily.
I am sorry if I came through as hostile, that was not my intention.
That is again a chicken or egg dilema. And yet, Japanese brands do quite well in Europe. It would be more accurate to say Japanese Premium brands do not do well in Europe, Europe has even no Acura. To sell with a markup you need a brand more than a product. I know you mention Audi as Premium, but looking at SUV/CUVs for example, a Q7 is in no quantifiable way better than a Touareg, they are exactly the same, yet it deamed a worse value because of the VW badge. So imagine how hard it is for any foreign brand, including Cadillac or Maserati.