That is not a reasonable comparison, given bitcoin's actual purchasing power (12 billion dollars for all bitcoins). If at the time when all of the world's assets are denominated in bitcoin and its market cap is several trillion dollars this wealth distribution remains, then the comparison would be valid. But as bitcoin grows the wealth of the top holders will flow into the economy and be redistributed. They will want to spend their wealth, not just hold onto it for the sake of preserving the status quo of vast inequality, which I am sure most of them realize is not healthy.
Why should they do this ?
If bitcoin succeeds in the long term they won't need more than 10 coins to be happy all their life.
Also , who can say for sure than 20 of the top 100 addresses are not owned by the same person?
