Regardless of whether Toyota launches the Century brand, wouldn’t Lexus still need their own flagship? If the Century brand is high above the Lexus brand it wouldn’t be cannibalizing sales from Lexus anyways due to different price points. Not saying you’re wrong, but it doesn’t make sense to me from a financial/logistical standpoint.I would like to add that we seem to forget about rumours considering Toyota Century. If it is true that Toyota Group plans to establish new ultra-luxury brand called Century positioned high above Lexus, it is fully understandable that they won't invest into new LS generation, because new flagship sedan will belong to the new brand.
At the same time, I still remember my Father's first Lexus LS in 2007. I swear, that car was The Chosen One.
Also, this is Toyota. Although I suspect that the Century brand will use a lot of bespoke parts to maintain exclusivity, they need to bring their overall costs down. Sharing things such as chassis for lower volume LS would make sense to water down cost. They can keep Century more exclusive with higher quality interiors, drivetrain, etc.