I would hazard a guess that the R75 owners are either enthusiasts who will make time to fix the ever increasing problems (just like any other car of its age) or people who got them cheap and will run them into the ground until something goes bang or they are fed up with niggly faults.
Big cars like the R75 Mondeo Vectra etc are now being substituted for Ford Focus size cars as they are cheaper to run and easier to park etc.
I made a living 10 years ago from selling Mondeos etc but even then I could see the demand falling away to smaller family cars.
Lots of belting R75s about but thats a testament to the owners looking after the car and doing the appropriate checks and services etc.