im not sure to which scale this is true, but TOR specifically is highly centralized, and by design I2P is extremely decentralized, with most nodes running network routing of other nodes. Not that it's impossible to do, it's just a lot harder, and not nearly as valuable.

A lot of the ways in which people are got over shit like TOR is just skill issuing. Don't run a drug empire on the darknet and you'll probably be fine. If you do run a drug empire on the darknet, you better be damn fucking good at opsec, and pretty fucking good at laundering money. And even then you'll probably still end up fucking it up.