Obviously the more invested you are in a platform the harder it will be to switch, but it’s intrinsic to platforms not a specific company strategy, if you move from Mac/Windows to Linux, the more free platform existing, it will cost you money; if you move from Linux to Mac or Windows, it will cost you money. If you move from iOS to Android it will cost you money, sure, but the same it’s true if you want to switch from Android to iOS.
Nobody questions there are natural switching costs between platforms, but the key part is that Epic alleges that Apple enacted a strategy to artificially increase these costs above what they could otherwise be, with the explicit goal of creating lock-in. That allegation by Epic is explained in the documents I cited In the post you replied to.
Obviously Apple strongly disagrees and refutes these allegations, but no matter one's opinion it's important to understand the narrative of both sides if one wants to understand why and what relevance the statements quoted in the MacRumors article have in the court case.