I think this is a pretty good problem, it's easy when you ask who is the richest, there's a lot of information on the internet with a google ranking, or a Forbes ranking, but those are the coins. clean money, blackmoney is still very much around the globe, some personal reasons they do not like to appear in public is also an example, in my opinion, money is never enough, the richest people have many health, time and having a happy family, always happy with life, living with your passion and interests, because money is only a tool only, if you have a lot of money and alone in life ... what is a lot of money for?
The richest people of the world are basically owners of big technology companies like Microsoft Amazon or Apple.
Indeed, as the world progress to another era, technology becomes the leading piece of the human kind. Unit of richness is money, money that can conquer all. I believe that these people are the perfect example of what is hardship is, we've known these people from different country in the world having their own story to be told, to the world. Owners of these tech companies proved what a man could do. I admire them all.
There are criminals who cannot be listed among the richest but I believe they hold huge amounts too. Rothschild is also a rich family by owning gold of this world. Let's just focus on the future rich guys because that is more important. They will be the Bitcoin holders of present.
Oh I remember the infamous Pablo Escobar. As far as I know he, himself became the richest man in the world when he reached 35, but wasn't that realistic since everyone knows what's his business does in 80's. I doubt there are already listed on the list that is a bitcoin holder, since these big people has financial advisor and econ. team on their side which are not in favor of digital, highly speculative and volatile investment.