That still serves the leftist economic end - reducing disparity, the gap between the rich and the poor, the haves and the have-nots, the insured and the uninsured, the healthy and the lame. Absolute measures of poverty are a facade used to trick the proletariat into accepting the "gross accumulation of relative wealth [and thus power!] by the bourgeois".
Take a room of 30 people - each is starving, engulfed in flame, diseased by leprosy, blind, deaf, and illiterate. So far, perfect equality - a perfect miniature society. Douse one individual with water to extinguish the flames and you have produced a bourgeois. While only the insane would suggest not to do the same to all others, a subset of apparently sane within our culture would prefer that lucky doused man to be reset aflame rather than permit the disparity in socioeconomic conditions to persist (if one were for some reason unable to similarly douse the other 29).
When the social disease recognized goes from poverty to disparity, as so happened when the definition of "liberalism" was perverted, a perversion of economic and moral thought should be expected.
I remember a joke that illustrates your point:
An American riding the bus sees a man driving a Ferrari and says to himself, “Some day I’m going to own a Ferrari.”
A European riding the bus sees a man driving a Ferrari and says to himself, “Some day that sonofabitch will be riding the bus just like me!”
And of course, conservatives represent the American view, and liberals the European view.
If liberalism had any correspondence to reality in this regard, I could sue Brad Pitt for being more handsome than me, win my case, and get my new Brad Pitt face and body.