As someone who genuinely believes that providing a legitimate (or as legitimate as possible) avenue for people to purchase drugs (I'm less sold on arms trafficking and sale of stolen credit cards) I was surprised to find how much a genuinely felt like I disagreed with the bulk of this articles content.
While I haven't been in the market for any drugs for a while I know enough people who regularly frequency DNM's and I tend to check in every now and then just because I find the whole ecosystem fascinating.
This article seems to imply that the entire dark net market thing is as simple as ebay or airbnb, but it's actually a lot more complicated. There's a ton of extra stuff you need to do to protect yourself not just from the vendor/buyer but also from the market places themselves, because they are also "untrusted" this means things like multisig transactions and the like are a must.
Additionally the view that a vendors pseudonym is important is just flat out untrue since people realised how much money there was to be made by hacking vendor accounts or claiming a known vendors name on a market that vendor does not yet have a presence on. The key thing is being able to do what is generally considered reasonably high degrees of security based validation, by verifying an identity out of band from the market. This means using GPG keys that you have sourced from previous interactions to communicate, double checking with vendors over wickr or secure anonymous email services to ensure they are the person you are dealing with on a marketplace.
Essentially once a vendor has a reputation the marketplace becomes irrelevant entirely. If it where me, I'd rather do a direct deal using GPG encrypted messages over wickr with a vendor I trust than buy from a vendor I don't personally know on a market that I shouldn't trust (exit scamming must be way to tempting).
I admit that I'm not entirely engaged with the current workings of the DNM's at the moment, but other than being a place where new vendors can earn some reputation, the value add isn't that high. And now that it's a mainstream activity (relatively to buying drugs in the open before silk road) I feel like it's only a matter of time before new vendors can earn enough reputation just frequenting reddit boards on the topic and making sure they have good opsec. As soon as they get one or two people happy with what they've bought, it's all word of mouth from there. (Obviously they need to deal with security of being on the clear Web, or just set up their own onion site)
With regards to a point that was mentioned about block chain history being useful here, it isn't. All it does is help law enforcement, unless you mix your coins appropriately through a trusted party in which case the history if your transactions isn't verifiable and it's useless anyway.
What are useful are services like grams, which (at least when I last checked) scraped reviews from market places, reddit, etc and aggregated them based on the vendors public key.
I feel like this article was either written about 5 or so years ago, or the information it contains simply hasn't been updated in a very very long time.