You're missing the point of the author. It's not so much that Docker as a technology is bad; there's nothing wrong with it. The point is that Docker, the company, cannot monetize upon the technology, because the moment they start charging for their containerization technology, people will switch to an alternative container technology, especially now that Kubernetes has won the orchestration "wars" and made it so easy to switch the underlying technology.
Personally, I have to agree with the author and think it's difficult to see a bright future for the company that lives up to its $1.3B valuation.
Personally, I have to agree with the author and think it's difficult to see a bright future for the company that lives up to its $1.3B valuation.