The entire discussion is predicated on the arrival of an AI future where AI can do any human labor at incredibly low costs and all but eliminating the value of human expertise. If getting something done resembles "doing everything themselves" then that future did not arrive.
The "incredibly low costs" part is part of the classic AI discussion, but it's not part of this AI discussion.
The article makes clear, it is describing not a hypothetical future trend, but the trend that we are seeing today, where you don't actually get that much more productivity by replacing people with today's AI, you actually probably lose more than a bit, but it's still a good deal for business anyway, because they would rather pay AI companies than people about the same amount of money to do about the same amount of work.