I found it to be believable.
Jokes aside, the point would be more compelling if the Apple apps at the top of the list all were competing against the apps being searched for, and if they included searches for apps that didn't provide functionality Apple did. The algorithm as I see it from the article is that the #1 popular app comes first. Of course Apple takes the top spot ... this is unfortunate winner-take-all promotion that in fact the entire software industry actually wants regardless of what they say or gripe about on medium (only upstarts complain, which ceases the instant they make it big).
So, then the #2-#k spots are apps by the same maker, which both serves to help the user discover other apps they mightn't have otherwise searched for (promoting use and engagement, and the app ecosystem per se), and helps persist the winner-take-all business model. By only promoting apps by the same manufacturer it maintains some odd definition of relevance.
Then after a run of same-manufacturer apps, we get back to #k-#n organic results. The user can very obviously and very easily pick out the fact that up to #k is pushing discovery, and that below there are the results they wanted. It's actually not a big deal (actively harmful) because of the irrelevance of the #2-#k results.
So, if they had bothered to include information on apps that Apple doesn't compete against (instead of producing a 1-sided story), for which there is a manufacturer who produces a very wide variety of apps, I wonder if you'd see the same type of results. #1 result being their super popular app for the search in question, #2-#k being other (unrelated to the search) apps by the same producer, then #k-#n organic results. Clearly most app makers are one- or two-trick ponies so wouldn't have search results like this. But surely there are some?
The point is, as written, it's a hit piece.