The German Premium cook book is not even a secret. It is clear as daylight. Or maybe there is a secret? Yes, but not what you expect. The secret is consistency!
To be profitable from a manufacturing perspective, you either need to lower costs (Toyota way: few options/customization but streamlined prodcution process) or make the customer pay for the extras/complexity (German Premium way: endless list of options, double the starting price).
The sell the first way is evidently a good value buy. The sell the second way you need the added value, and that is what brand perception does.
That is where what the Germans do is evident: brand desirability with continuous halo products, entry level products to appeal to the all (make everyone feel special) and all this has to be supported by marketing, a prime cornerstone. But the secrete is to remain peristent and then consistent. That is where every other luxury car maker failed, Lexus is the last standing alternative.
An example of how this worked is Audi. I don't have to describe what they did, it is self evident (still don't forget marketing). They were not BMW/Mercedes equal.
One difference between Lexus and Audi is the Lexus profit from Toyota's reputation but Audi have their good reputation and make VW profit from it ("cheap Audi" rather than "expensive VW"). But this can vary regionally.
So back to the secret, a Lexus GS, while great for some customers, is not a solution Lexus situation if marketing is not done (which was not as it should) and if consistency is not there. We'll see how persistent and consitent Genesis will be, that is if they first apply marketing tools as must be done.
PS: Rolex does marketing, like no other. It is no Vacheron Constantin. Rolex is the BMW of timeprices. I'd take a Girard Perregaux or even a Maurice Lacroix over a Rolex. (But I'd gladly take a Rolex Oysterquartz, the only true Rolex for me.)