Believe it or not I wasn't going for sympathy, I was just making a point that low-mileage drivers are just as likely to contribute to the economy as high-mileage ones. Your example of "wives in their sporty convertible going to Tesco's" does seem rather dated.
It is annoying, I pay £280 a year VED for my car because it has pretty high CO emissions. However, I only do about 5-6,000 miles a year so if it's based on environmental impact I'm doing less damage than someone who pays say £90 and does 20,000 miles.