Cars are for driving. If I can drive them as a hobby and not lose my shirt then that's great. Not sure I need them to be investments too...
It seems to me that classics with very low mileage get to a stage when it's all about preserving the low mileage rather then enjoying the car - they can't be driven because that low, low mileage has to be kept low.
Some models are so expensive they can no longer be taken onto those dirty, dangerous roads - when was the last time you saw a DB5 going by?