It makes sense that you lose out on customer insights/problems when you're reliant on a help center FAQ to answer questions. Essentially losing out on free customer development.
Help centers, along with "self-service knowledgebases", are just ways of making it harder to find the contact us page.
That's sometimes true, but I think (like mentioned in the article) a combo of a knowledge base with clear ways to contact a human usually leaves a good taste in my mouth.
interesting post; especially notes on increasing revenue.