I don't know about the richest but a lot of wealthy people have already put a lot of money in bitcoin. Obviously they don't need it as a currency but its a very good asset and a nice addition to any investment portfolio. I think the more interesting question is if rich people will/are putting big sums into altcoins, i know there are a lot of altcoin whales but its unclear if that's new money or people who earned it big from bitcoin and previous altcoin pumps.