I suppose that is one possible future.
From the article, the reason API marketplaces will “win” is that market forces will force evolution and the very best APIs.
There is similar argument about online university classes. Once the “very best professor” has recorded the very best lecture on a topic, why would anyone else bother to lecture on the same subject? Yet students keep going to Universities and listening to lectures by all the other “not-best” professors.
Of course, “best” API is hard to pin down (like best online course). How do you measure it? Is it quality, cost, ease of use, security, speed, availability, understandability, reviewability, secrecy, not-invented-here-edness, etc?
Business will always find reasons to want to differentiate (aka compete).