Americans do not see Volkswagen the same way Europeans do. Volkswagen occupies a lower end automotive brand image in the United States. An expensive luxury sedan aimed at a small number of people won't fix what Volkswagen calls a disastrous operations in the USA. They can give this car the same Bentley engines, the same platform, and a bargain price and it still will never have the sales or curbside appeal of a Bentley. Seriously Volkswagen, a Bentley with a VW badge won't save you.
Focus on bringing fun, affordable cars. Embrace your entry level market. Mercedes and BMW are increasing their offerings in the entry segment and where you should be beating them is by offering a greater value. That, or create a Volkswagen luxury sedan that overlaps with Audi and approaches $100k. If you think that latter makes more sense you deserve to struggle here.