@martinbo as well
6er Reihe was a child of a very difficult era. Mind its precursor was the BMW Z9 Coupe & Cabrio Concepts - which were vehicles of one class higher & one size bigger than the actual production version of E63 6er ... and were actually 7er based.
Z9 was planned to be a new generation of 8er but it was reduced to smaller, cheaper 6er. Then another attempt of 7er-based 8er revival was scraped: project Gran Turismo.
So, BMW are returning to the original idea: reviving the 8er coupe & now also cabrio. While 6er is now positioned to be "a new era gran turismo vehicle": offering effortless travelling in style & comfort. And today effortless travelling / driving is all about roomines, comfort & also about semi-command sitting position. Original 6er was a GT of its era, today's 6er GT is a GT of today's era.
Also GTs were once kings of twisted rural / mountain / coastal roads ... Today's GTs are more of an Autobahn cruisers.
Also, the BMW GTs have their own customer pool & followers. It's a niche. But still bigger one than the one of classic bigger coupes like 6er coupe or 6er gran coupe.