There are billionaires worth over $100 billion, and even more worth between $10 billion and $100 billion. So why haven't any of them bought most of the bitcoins? They could have done so, for example, in 2020, when the price of bitcoin was $5,000-$8,000. Bitcoin's market cap is now less than $2 trillion, and it used to be even less. Some multi-billionaire could have bought at least 10% of all bitcoins, but why hasn't anyone done so?
If I may ask, do they really need it?
Some of us are buying Bitcoin for benefits or interest rather than as multi-billionaires. I don't think they would really have time for mining or investing in cryptocurrency, although some will not even give a damn about the cryptocurrencies, and if a multi-billionaire decides to buy all the Bitcoin, the market wouldn't be funny, which I don't think it will even be possible to do due to the risks of investments. Moreover, a multi-billionaire will not only depend on one asset.