Right now we have vulnerability assessments and penetration tests. There are still people who confuse the two. Chris Gates (author of the article) is talking about another tier emerging in the field: attacker emulation.
Right now penetration test can mean many things. It can mean a standard CEH/CISSP/other cert trained monkey running tools and generating a report from within your DMZ for two weeks. Or it can mean a dedicated team spending their days like a stalker in a dark basement putting LinkedIn profiles and IP addresses on a cork board until they see the opportunity to strike.
They're different tests needed for different situations. I do not know how big the market will be for these advanced tests, but some organizations need and will pay for them. It's fun work if you can get it.
So the article is drawing this line and saying: "hey talented guys, there's real work for us… we just need to be aware of what it is and not get discouraged". Penetration testing isn't dead, it's just becoming automated and the lower tier of it is becoming more well defined. The cool stuff still exists, we just need to call it something else.
How's that? As for making a career out of it? I'm not. I pen test now, but only because it's fun. Once the fun wears off, I'll go do something else.