I mean, they are so rich, they can start to mine Bitcoin, even if they lose some money they shouldn't care, they are ok with all those money they already have.
one thing about "getting rich" is that it's never enough. people with a lot of money tend to want more and more. the richest people i've ever known have also been the cheapest/stingiest, unwilling to spend money on anything. that's partly why they became rich.
it's also not easy to just start mining bitcoin. with the difficulty trend and unreliability of prompt shipping of miners, you need to be extremely well capitalized. you'd probably need to dump several million $$ into a well planned mining operation to be viable. in order to do so, you'd also need to sell a shitload of your BTC to cover overheads, and you'd have to pay capital gains taxes on all the gains.
If you became rich and you are doing the dream life that everyone wants is thanks to Bitcoin, don't let him die.
fortunately, there are some good souls who are early holders. see
https://pineapplefund.org.
With bitcoin reaching new heights, we're donating a massive amount of BTC to charities and causes all around the world. 5,057 BTC ~$86 million USD total committed. 4,646 BTC ~$79 million USD remaining. 9 charities supported so far. View the address: 3P3QsMVK89JBNqZQv5zMAKG8FK3kJM4rjt.