There are new markets being built but non of them are gaining any market share. What would it take for a freshly created market to succeed? Its better as a whole that the user's of DNM are distributed evenly across all markets since one exit scamming wont hurt the entire community.
A lot of things. Here are some things:
Just look at all the big markets from the past and the present. Silk Road, Agora, Abraxas, Evolution, Alphabay.
Do your research. I really think that the design of the marketplace is very important, cuz nobody wants to browse a marketplace that looks like it came straight out of someones asshole. Should be easy on the eyes and enjoyable to browse. Also, you can check out how AliBaba works or other big Clearnet markets. Customer service and other shit I cant remember once again.
Conclusion: Getting a market to become big doesnt take 5, 10, 100 things. It takes millions of things, every little thing is important. If the system aint secure, how can you be sure that your identity is?