There are bound to be many more incidents such as this in various cryptocurrencies. There are now thousands of them. But it would be ignorant to dismiss the technology for a lack of understanding it.
The analog in national currencies would be if everyone had to immediately stop using the old notes and replace them with new ones that a new anti-counterfeit feature. Or migration to the Euro.
When banks are hacked or whatever, they have some kind of insurance that just replaces the money. They don't have to get the rest of the system to update anything.
{!} Thanks to today's progressive reforms the State now also employs women with guns. We should just say people with guns to not be sexist.
Foreign shell companies are already hard enough for most governments to deal with—and that's with trade agreements that enable them to compel disclosure of ownership. DACs are foreign shell companies without a governing state to point guns at.
Sure, if the DAC does business in the US, the US government can shut that business down—much like the US government can shut down a domain name associated with foreign illegal activity. But that doesn't stop the business from operating anywhere else. Nobody has the ability to shut down the whole business.