I was reading about Cashaa, that was hacked and 336BTC were stolen. But the hacker can't move them right? He will leave footprints. So why should hackers steal them since they can be found? For example if they want to convert them to fiat.
The only way I think you could get by from this felony is to keep them on very long term. So long that it may be forgotten. But still, it may.
There will not be any hacker anymore if the case as you said. If the hacker still trying to hack some exchange and steal bitcoin and all the victim's asset it means they have many ways to cash out digital currency into money fiat. In the digital form esepecially in the internet network we can't expect which is really clear because you will find another ways to open which you really have never seen before. Like a few years ago, many government banned bitcoin and crypto currency to use in their country and will be jailed for those citizent who still using. But in fact, that was a useless thing, you still have many chance to use bitcoin and traded it freely.