And it was still quite literally used by 10,000's of vendors to sell illegal drugs?
I dont think it would have even been a thing if it was as easy as you suggest to catch people selling drugs on it. Sure, with enough resources, a dedicated law enforcement team can likely bust a drug dealer using BTC; but like with most things involving drugs and Neo-liberalism, the prisons are all full, the police are underfunded and can only occasionally make token arrests and the people who arent low hanging fruit get in and out without any interaction with the police.
The people in prison for dealing drugs arent the same people dealing drugs with bitcoin, you conflate gang members, prescription drug resellers and corner standers with the profile of a typical darknet drug dealer, which arent the same demographics for the most part.
Its the reality in the UK at least, only drug dealers who get caught here are the ones trying to ship in millions of worth of cocaine, the prisons are actually all full here and most drug crimes dont even get charged because the time limit they have to charge people expires by the time the courts become available.
As for the US, it remains a convient excuse for the police to suppress votes from demographics the upper class needs supressed; you wont be finding the people who supply elon musk with ketamine going to prison anytime soon, they will be smart enough to use monero!