Obviously he was also working for the Feds at some point. That is the only explanation for how he didnt end up in prison.
Kind of backs up some of the conspiracy theories that were floating around in the 90's about the Feds.

So based on the statute of limitations they couldn't seize his assets? And btw- he said at his high point he was making about $200,000 a week for himself, not $1 million. He was making $2 million a week for The Godmother and taking home $200,000 for himself. He also said multiple times that his net worth at its highest was around $20 million, give or take. One thing people don't realize about this business is that because so much of the money is physical cash, it's easy come easy go. So you might be like Carlos Lehder, who for a time was a bona fide billionaire. He had something like $1-2 billion in cash just laying around from all his wheeling and dealing and then he lost it. I think he lost it through his involvement with a guerilla movement somewhere. Anyway, he lost all his money and had to go be Pablo Escobar's body guard to make ends meet. I mean, he was paid ridiculously well and was only a guard in name, but to go from being a literal billionaire to being someone's body guard tells you how fleeting and precarious wealth was and is in the drug game.
Brian Peppers is my Homeboy

Its called statute of limitations. Charles Cosby hit a certain dollar amount and walked away. With the exception of murder (and maybe sexual assault but I'm not sure) every crime has a statute of limitations, meaning that if the police don't charge you within a specified time (its 7 years for trafficking) they lost their right to prosecute.
The police had no clue (from what I understand) of Cosby's dealings. When he lost the Colombian connect, he "retired". I mean dude was making $1 mil a week or so, he had to have put some away.

he already did his part

same question here