The only problem governments have with darknet markets is that it is taking their business away.   Being the monolithic abominations which they are, it is inevitable that government will fail. 

In the mean time...   Openbazaar2 Alpha running over Tor is out and Bitbay allows you to create what you want in their private namespace but I think the future is in Sky. 

They have created a new darknet from the protocol level up with all traffic encrypted by default based on open design hardware and an entirely new namespace . Completely decentralised internet.  The first application for sky is a redditesque BBS about to be released and there has been quite a bit of talk on the Telegram channel about a decentralised marketplace. 

Keep an eye on this one.