Your citation has nothing to do with Apple banning apps and the idea the article cites is as old as dirt and has been discussed since way before the App Store.
There is no copy cats rule. There is an existence proof that this isn’t true in every category where Apple bundles a first party app.
That is not what they are referring to. For some strange reason there is a myth that you can’t ship an app on iOS if Apple has a competing service. Even though there are all sorts of existence proofs that it isn’t truth.
Here's an article that goes over some of it (although it oversells Apple's first party advantage I think)
https://www.washingtonpost.com/technology/2019/09/05/how-app...
Apple also has a no Copy-Cats guideline that has been used to push out some apps, although maybe its not wide spread enough to be a concern.