Earlier quoted context omitted.
It's not that hard. Do what you would do with a large amount of cash or gold coins: put it in a safe deposit box. Or a private vault, if you're ideologically opposed to banks. Unlike gold, you can also add redundancy and cryptographic protection, but even without that you can at least be as secure as you are with gold, which plenty of rich people store in vaults without issues.
People are idiots. It's almost impossible to destroy gold, quite easy with bitcoins.
But it's also easy to store bitcoins in a way that makes them hard to destroy.
Idiots destroy wealth in all sorts of stupid ways.