I see that article as mostly hyperbole, weakly based on projected emotions of Musk.
Musk won’t absolutely need his own phone, either, as Gab has already been long working around app prohibition by simply building a better browser interface, which Twitter could easily do as well.
His recent actions are more likely about Musk wanting to turn Twitter into a financial system, which he has hinted at, and trying to publicly barter with Apple (and Google) about operating costs on their platforms. Replacing those platforms would cost a whole lot more than just paying their tolls, for now.
All true.
The 30% fee charged by Apple is the same as the 30% fee charged by Google. Both are constraints upon free enterprise.