A very rich person consumes even less than an average person, as far as tax authorities care, because a rich person has his expenses paid by corporations that he owns or controls and these are deducted from their earnings, so quite a big part of his expenses are virtually free of tax.
A rich person also does not use much more fuel than a middle class person, does not eat or shower much more than a middle class person, does not have many more electric products owned directly by him etc.