[jxramos]

Yes, I'm starting to awaken to the fact that at this point we're no longer talking about income but disposable income. The points about what you're calling essentials. I'm trying to think about this mathematically, this is what I'm feeling out so far...

Premises

    X = income
    c > 0 (income difference)
    p = tax rate
    e = some expense

    ==> X+c > X   (income inequality)
    ==> (1-p)(X+c) > (1-p)X   (income after taxes)
    ==> 1/[(1-p)(X+c)] < 1/[(1-p)X]
    ==> e/[(1-p)(X+c)] < e/[(1-p)X]  (expense relative to disposable income)

Like with many things people mean different things by the same terms. I'm thinking more along the lines of the second investopedia article which makes the point of This type of tax has no correlation with an individual's earnings or income level.