They had to know what kind of scrutiny would be on those coins forever.
At the time of the theft, the coins are worth $100M+ and they can't touch them. Even worse, anything they do with them will be monitored, researched, dug into, and everything else from law enforcement, amateur detectives, and every major tech+crime group.
Fast forward to now and the coins are worth 50x that.. and now they try to move them? And all the keys are in cloud storage? But it had to be frustrating to be sitting on something so valuable without any way to use it. They had to be stressed and anxious about it.
A life of crime is stupid. A life of crime for something this high profile is far beyond stupid.
It's a slim picking...
Iran North Korea Syria Bhutan Taiwan Azerbaijan Palestine Georgia Cyprus Western Sahara
Even Russia has too much to lose. Maybe if it were $360 Billion, they might consider it.
At least in half of those countries, once they found you really in control of $3.6B crypto, they would torture you until you give it all, then dispose off your body.