Earlier quoted context omitted.
Those examples I was giving did provide lots of value, to the client. The section from the article was talking about optimizing for visibility. Deep technical problems with lots of value are not always visible, and I think it's fine to build a career around those types of things.
I wasn't disputing what you said, kind of agreeing with it actually. Although as a consultant for over a decade myself I have to make an effort to make sure my work is visible. I'm not sure I could lurk in the shadows with no one seeing the value I create and still get paid :)
In my experience, if you do good work, it's usually not that hard to get more work even without a public showcase of your work. Your clients will come back the next time they need to get a job done. Your clients also tell others about you, and word-of-mouth is extremely valuable advertisement.
I guess promoting yourself on Github and on personal blogs is one way to go about it, but real life personal relationships shouldn't be undervalued in my opinion. Most consultants I know have a surprisingly bare website.