Because not everyone is behaviorally/psychologically wired to be an innovator. Actually, surprisingly few are.
But if we’re not free to compete and innovate in a relatively untrammeled fashion, innovation dries up because the ample reward for this very beneficial activity is “removed and redistributed”.
Those who do not innovate (are not Bill Gates) — otherwise known as “everyone else” — still benefit greatly from the innovation (how many use the toilet they never invented?). So it is in everyone’s best interest to continue amply rewarding those who can be exploited for the benefit of so many. (A manifestation of the Pareto Distribution, also called Price’s Law or “The Matthew Principle” as mentioned in the Biblical book of that name.)
But then too much inequality destabilizes the system (the Gini Coefficient).
We don’t yet have an answer to this. We can identify an measure the processes that manifest. But radical social reconstructionism and/or enforced wealth distribution has never proven a good solution.
Should we continue looking for solutions within a system that is imperfect but has produced a lot of beneficial innovation, raised so many out of abject poverty world-wide AND awarded the best degrees of personal rights and freedoms to the individual?
Or dabble in radical social reconstruction — particularly in light of where almost every exercise of this has ended up?