I believe this is because most of them are young and smart. Smart enough to understand the idea behind Bitcoin, smart enough to know how to operate it too. Unlike these older rich men who because they don't understand how Bitcoin works(or how to operate) have lost interest and are always discouraging others.
Yes, usually old people who have wealth will choose a business path that is more certain and does not have a very big risk. In general, older people are very afraid of trading cryptocurrencies because their prices are very unstable.
Now many young people are trading crypto because they think that cryptocurrency trading can bring wealth in the near future and young people are now more aware of today's technology such as computers and mobile phones.
Younger generation are more open to high-risk investments, so to speak.
Also, when it comes to crypto, it comes very handy to these millennials as a lot are glued to their gadgets.
So for them, it is easier to get on board in crypto rather than breaking their neck understanding the economics of certain business.
And as we are in digital era, most of these younger people are oriented to do their activities online, in which, they can easily encounter crypto market.
All the info that they want, can now be reach if they know how to get around the net.