Hooper Bentley Empress II.... defining depreciation

Advertised for £350,000.00 in 1991. In todays money, according to http://www.measuringworth.com/ukcompare/result.php?use%5B%5D=CPI&use%5B%5D=DEFIND&use%5B%5D=WAGE&use%5B%5D=GDPCP&use%5B%5D=GDPC&year_late=1991&typeamount=350000&amount=350000&year_source=1991&year_result=2006 was worth £771,303.41 in 2006 ... about what they were asking for a Bugatti Veyron. Yeah, the million US dollar car. So why