Basically they are rich now because they invested and they are not easily sell for a small hype of bitcoin as you can in the graph or chart of the bitcoin, The bitcoin price is growing since it was created so if you sell in small hype you will just lose the opportunity so I think they have the patience to wait that's why they are rich now.
Not just the patience it takes to be able to hold bitcoin for a long time. But also their belief in bitcoin. They will be patient as they believe that bitcoin prices will reach $ 2500 someday. And that's what brings them rich