Of course the 5% of "Product Guys" and "Business Analysts" that are true talents are worth their weight in gold.
So, what are they paid to... do, then?
As the article says, not all of them are useless. Some business analysts provide very valuable insight, and a manager who has come into contact with one of those will want to hire more of them. By the intangible nature of their value though, it can be hard to judge whether you've hired a good one or a leech.
Thrash around trying to understand the business. Some will be more successful than others, depending on how smart they are. Some will gain a superficial understanding and claim to have mastered the domain, but let's just say there's a different kind of "OA5" person who often ends up in the job.
Occasionally, if you're lucky, you'll find ons that has a vague clue about how to write requirements. Or design UI. Or that cares.
(speaking as a Product Manager / UX Designer / Developer, not necessarily in that order)