I assume that a CX will cause considerably higher maintenance costs in old age than a Trad. It is a complex car from a small series manufacturer.
I'm sure you are right for people who don't do their own maintenance, I don't believe it would be necessarily true if one were to do one's own maintenance. The B48 engine is a well-known unit and can be maintained with the help of aftermarket software like BimmerCode.
Although the rest of the car is also more complex than a trad and this would result in high labour costs if having work done at a dealer, if doing stuff at home it would really just mean maintenance tasks would take longer. I'd happily take one on, but then I have a good range of tools, a big garage, and a lift. I wouldn't be so keen if I didn't have those.
