might i offer that the observation of activity in these slices you propose, if there is not accountability of potentials, is lacking in information needed to accurately assess an economy, or any matter which can fall on a timeline? such a snapshot of two cars neck and neck in the middle of a race cant deliver any real information. if one of the cars is accelerating and the other decelerating, the implications of the freeze-frame are moot, so long as potentials are not considered.
economics instead works with the idea of perfect markets. real markets do stray from these ideals, but for the most part, they adhere to their general principle, barring scenarios such as your 'there might be no friday' or deception on the part of the parties. in such markets, the pie is not limited between participants, and potentials are worthy to consider.
ultimately, you go to work because you would prefer to spend your time doing what i say, than spending it on your own agenda, given that i pay a satisfactory and predictable amount for the privilege and don't ask outrageous feats of you. your work facilitates my income as well, which is in turn the result of a similar contract between our organization and our customer whereby they have forfeited what they think is fair for a service or product they prefer to the cash itself. in this scenario, everyone has participated in a way which they have profited, or they have otherwise acted irrationally. barring this imperfection in the market, this mutual gain by all parties affords the overall economy a positive, win-win-win disposition. the pie is not equally distributed, total economy produces more wealth than on which operates without the freedoms entailed in this model. just because the employee makes the least form the transaction (which isn't always the case) doesn't mean they were lied to or treated unfairly.
you are talking about different things.
There is a really really great argument to be made that society as a whole rewards everybody who participates within it.
But the suggestion that current wealth disparity or other disparity is offset by future potential is as often as not a kind of deception. For example maxims like "work hard, stay in school and _____and you will succeed" are often flatly false.
From a risk assessment perspective or a career planning perspective you would want to consider potential. But if you are a second generation Guatemalan competing in the workforce against third generation Ivy league trust fund babies the prospects of future success do not offset current disparity.
There is a long history of indoctrination for the world's poor that involves placating their current grief with future promises, the most famous of which is the age old promise of rewards in heaven for good works on earth today.
Anything to keep them harvesting the sugar cane or carrying peat on their backs to the King's castle or voting dem even tho Obama sucks!