Even so, the article doesn't explain how he did it in a way for a non-computer and tech savvy housewife to use similar methods to discover what her husband has been buying.
Sure it does. Email Chainanlysis, ask them to de-anonymize a few Wasabi transactions for you, pay their fee, job done. 
However, the problem is that inputs are just half of a transaction, neither coordinators nor blockchain analysis firms can map inputs with outputs unless malicious developers introduce some vulnerabilities or backdoors into the protocol which will weaken the coinjoin process and make links between inputs and outputs less non-deterministic.
A way of doing this, which is trivially easy when the coordinator is working hand-in-hand with a blockchain analysis company as is happening here, is for the blockchain analysis company to put forward a few dozen of their own inputs to be coinjoined. The coordinator then picks (for example) 19 inputs belonging to the blockchain analysis company and 1 input belonging to you. You think your outputs are obfuscated, but the blockchain analysis company knows exactly which ones are yours by process of elimination.It should say that the company is working to make Bitcoin fungible.
Non-fungible.