Silk Road was a drop in the ocean, in total a hundredth of a percent of just the United States' spend on the most popular illicit drugs.

Silk Road … facilitating annual sales estimated at almost $15 million.

https://reason.com/2013/04/09/bitcoin-vs-big-government/

Researchers estimate that from 2006 to 2016, the total amount of money spent by Americans on these four drugs fluctuated between $120 billion and $145 billion each year.

https://www.rand.org/news/press/2019/08/20.html