"we" are society deciding on an economic system and taxation regime.

"we" currently reward people with this amount of wealth generally because of a majority belief in one or more of the following (none of which are true in my opinion):

  (1) They deserve this money, because either:
    (1a) it represents a proportional reward for work put in
    (1b) any money gained under a market system are deserved/earnt, and taxing those earnings is stealing

  (2) That rewarding people in this manner (without limits) is the only way to motivate people to work hard, and that this ultimately produces better outcomes than distributing our economic output more evenly

Are you absolutely sure that you and Bill Gates live under the same economic system? Because I suspect that you describe some other economic system than capitalism.