I can tell you that there are a lot of people thinking of ways to completely decentralize online marketplaces. It is a technically challenging endeavor to say the least, but I wouldn't be surprised if in five years there is a massive, leaderless and fully decentralized marketplace. Of course anything would be available, it wouldn't be drug oriented, but drugs would be on the list of available items. I will be surprised if in five years we are not using something based on Bitcoin, but I will also be surprised if in five years we are still using a centralized marketplace.