Outside of Bill Gates, I wouldn't be shocked to see someone like Masayoshi Son investing a significant amount, especially with all of the money he just raised. Additionally, Bill Miller, a famous portfolio manager, recently announced he put 1% of his net worth in BTC.
Lets ask a question `what is for one million for a billionaire?` We all know the answer, nothing, thats why they invest in everything a lot in my opinion.
Put 1 million on 10 different places and if just one investment is x100 he earned a lot. I think all of them have some bitcoins, or some other coins also, they sure don`t search for it they have advisers that do that for them, they just give the money and take profit.
If someone is a billionaire and didn`t invest in bitcoins already that man is a fool in my opinion.