Not actually true at all how you described it. Yes they can do asset seizures not only for drug cases all criminal cases usually at felony level. Proceeds or things used to commit the crimes can be seized through a separate civil process. Reality is the courts are super harsh and the civil lawyer get rich system (yes all the politicians, judges, and most lawyers share the same bed) causes agencies to not do what they may be allowed. Please understand the current defund the police and restrict the police has been building and coming for the last 15 years, and taxpayers at least for America do not want to pay the cost of the protections and prosecutions of criminals. Especially at the extreme waste and laziness of the system.Also, we know the country has become anti police and defunding them for the last few years. So one way the departments get money is through drug enforcement seizures. When they find money and prosecute through drug task forces, they can use that money for purchases for the dept. So their efforts are absolutely focused more on those crimes than websites which garner them $.02. And that's if they even find the people behind the fake sites, with the fake ID's.
As far as the web site issue and internet scammers the major majority of state level and lower agencies do not have the equipment nor staff to do the investigations they are limited in handling by jurisdiction and laws in place. The only agencies who can finalize the major majority of investigations are the Fed alphabet soup group and they just flat refuse to due to lack of manpower and funding. This has been going on since the internet and worldwide tech came into being. The federal government does not want to stop this and counts it as the cost to its citizens for what they are allowed to do by their citizens and countries abroad.