Rover's have always had that reputation. They were seen as a bit staid & mundane. The P6 alleviated that a bit being so unusual & forward-looking but the rep' has always stayed with them to a certain extent.
They also had a loyal customer base which tended to stick with them & if they weren't of a certain age when they first got one, they were when they got their last. :D

I've had Rover's since l was twenty years old & was an admiring schoolboy too.

Is it a Granddads car? - who cares when you travel in such comfort and style yet still have the power to burn off those sat in Euro boxes at the lights. :}