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.
The market is heavily driven by speculation and hype about future adoption. That's why we have these bubble cycles. It's a nascent market and early adopters are exposed to relatively high risk.
Clearly though, it's becoming increasingly established -- major institutional involvement and CME/Cboe futures markets reflect that. They know which way the wind is blowing. Even JPMorgan realizes now that BTC might stand alongside gold as a hedge asset.
It'll definitely become mainstream to own some BTC in any diversified portfolio. It's just a matter of time.
CME and CBOE futures were the effect of FOMO, from the exchanges. The volumes there are too low compared to other mainstream commodities. I think it will be a long time before it will be unusual if you don't have some crypto in your portfolio. Even if the rich know about it, I think they would perceive it as some sort of speculative investment.