It wasn't serious and I plucked the 100 million figure from elon musk since it's roughly his total investment in tesla and space x if I remember right. (although that was obviously in dollars and a lot more than 100 million of them)
You have to allow people the opportunity to achieve great things that will benefit mankind.
elon musk types aren't the problem it's the ones that are never going to put the money to any use and it will never benefit anyone.
Even these people aren't a problem, they don't take the money out and hide it under their bed. It all goes into investments or banks which helps everyone out.
I suspect it was more. He put an initial 100m into spaceX then when the first to F1 failed to reach orbit he put a second lot of moneys in.
There's plenty f issue, but none really are the rich.
Many are made due to law.