I thought...
The hype about the dark web is it secure from the monitoring of the local flatfeet if you use TOR or a VPN. I guess no one figure out delivery of goods and services requires outside parties to be innocently involved and will create a paper trail in meat space. If you are shipping drugs for delivery there is a carrier most likely innocently involved such as FedEx or DHL. The shipping documents automatically create a paper trail of the pickup/drop off point to the delivery point. Both are points that can or are monitored. Plus financial transactions even with Bitcoin create a paper trail that with patience can often be traced.
The problem that most have is the local flatfeet have been doing investigations using shipping and financial documents for a long time and they are pretty good at knowing what to look for.