It seems to me that many rich people are afraid of the unpredictability of cryptocurrencies. This market can only attract speculative capital. Perhaps last year we saw a massive entrance of speculators. In December, they began to leave bitcoin and now we have returned to the real price of bitcoin which does not meet our expectations.
Even if they are afraid of its unpredictability, they can still do something so that they can profit from it. It may be hard for them to manipulate a high volume market but when it comes to altcoins that has low market capitalization, they can still pump and dump it. They can manipulate the news and make people believe that the coin is undervalued so that more people believe it and then later on dump it to the retail traders.
Bitcoin has been hype last December and we are back to the price it is suppose to be when it would have grown organically since people are buying now when it reach $6k which would mean they think that bitcoin is undervalued in that amount. As for the richest that a third of them has been well- informed, I think they are just used to traditional markets and are not joining the bandwagon for bitcoin because of its legal implications that is still scrutinized.