Isn't this why so many high-value cars depreciate so much in later years? It becomes prohibitively expensive to replace parts with originals, so they get other bits and pieces put in instead. It doesn't really matter if a £10k car has non-original modifications, but on a £100k car it's a much bigger deal indeed. So to preserve the value they don't get used.
II remember about 15 years ago I was up at Kevin Vernon's and he had a Bentley Continental there. It was less than 10 years old, but had a high mileage and was worth a surprisingly little, less than £20k or so IIRC. I found it amazing because to all intents and purposes it was an extremely well-looked after car. But as Kevin pointed out, servicing costs were astronomic, as were parts prices.
