It's a silly topic to spend (waste) time on, but I can't help it, I just find it sort of fascinating.
It's a mystery where you have to try and put together different pieces of evidence, match things up, try and look for hidden connections - a certain type of human mind (mine, I guess) just finds that process rewarding.
I've gone down most of these rabbit holes and my 2c is it's one of these two people, not any of the most common candidates: Len Sassaman or Paul Le Roux.
Sassaman is dead and Le Roux is in federal prison in the US, which explains why the coins haven't moved
Le Roux was not in prison before 2020, it makes no sense to me that he was spending his time trafficking drugs when he was sitting on billions.
Of course at this point the only "sane" reasons for someone to not touch the wallet is that they are sitting on so much BTC anyway, they don't want to cause the price to drop, or the keys are lost (but the person is alive), or the person is dead.
If someone has access they can hire security for a few billion dollars and still have some change.
If we count "insane" reasons then of course there are quite a few more. Such as ideological motivations.
Your timeline is a bit off - he got arrested on 26 September 2012 (around the time Satoshi disappeared), and he became a DEA informant after his arrest which is why he didn't finally get sentenced for 8 years.
So at the time of his arrest (after which he was in federal custody and the DEA were monitoring all his use of electronic devices) Bitcoin had only been in existence for three and a half years.
The drug trafficking and Le Roux's various other criminal enterprises all started happened in the mid-late 2000s, before Bitcoin was worth anything
We'll never know but I honestly think it might be him, there's other evidence:
Commonwealth English speaker (grew up in Rhodesia/SA) - Sassaman was american and it would be odd for him to adopt British english as Satoshi
Known Windows user and there are supposedly similarities in the tech stack and code between early Bitcoin client versions and TrueCrypt which Le Roux is widely believed to have developed
Early Bitcoin client versions included poker game code for some reason - Le Roux is known to have been interested in this and at one point was considering opening an online casino
On the other hand, evidence against Le Roux and in favour of Sassaman:
The whitepaper has weird references that suggest the author was involved in cryptography academically in the Benelux countries. Le Roux did live in the Netherlands at one point but afaik wasn't involved in anything academic whereas Sassaman very much was
It's a mystery where you have to try and put together different pieces of evidence, match things up, try and look for hidden connections - a certain type of human mind (mine, I guess) just finds that process rewarding.
I've gone down most of these rabbit holes and my 2c is it's one of these two people, not any of the most common candidates: Len Sassaman or Paul Le Roux.
Sassaman is dead and Le Roux is in federal prison in the US, which explains why the coins haven't moved