I can't stand this malthusian, historically myopic, zero-sum thinking.
Using that same distribution, if I started a business, hired 99 others using half of the equity, then we sold it and I ended up with $500 million, should this inequality be a concern? No. the concern should be whether or not there's real suffering taking place with how that other $500 million is allocated, and the purchasing power it has relative to the past.
If you show me an economy that I can easily increase my real wealth by 5% per year, I don't really care what the guys on top are doing. What toys they are buying. I do care about them buying power, and they can only do that with a weak/corrupt political system. As PG reiterated: attack the causes, not the symptoms.