I don't think that conclusion follows from the premise. I could also mop the floor and clean the windows at work, but that doesn't mean that it would benefit the company overall. Similarly, just that engineers could in theory explain the thing they do to e.g. a customer does not mean that they should spend their time doing this. *
There's further nuance in that (in my experience) engineers tend to be, by default, not great at communicating at the right level with a lay-person (which is more or less the point of the article), and that hiring people to interface between e.g. customers and engineers comes with pitfalls and can go wrong (your point, I believe). I personally think it's best if someone who presents products to customers has a deep engineering background and has transitioned into their customer-facing role from there. But if you need to visit more customers to make more sales, hiring more sales people instead of drawing from your engineering department is probably a wise choice.
I say these things as an engineer in the trenches.
* To be clear, I have no intention of disparaging either job.
