Rust is not surprising! Phaeton, as the highest-level car in the public standard, used almost all the patented technologies of Audi A8 6.0 W 12 in order to open the market, but Audi didn't just give one thing: all-aluminum frame body (ASF). I don't think it's worth it anymore. After all, Audi is its own brother and face (high-end brand) and can't kill each other. Therefore, it is normal for steel structures to rust.
Because of its heavy weight, high fuel consumption and no aristocratic lineage (popular standards represent grassroots), even if the last German Chancellor Kohl personally acted as the spokesperson (Phaeton was his car), the factory building was pure glass. The transparent factory is a gimmick, but it still has little effect and little sales.