Apple's iMessage app has never been available on Google’s mobile operating system, and according to depositions and emails from Apple employees and executives, there is a clear reason for that: Apple apparently thinks it is one of the reasons people don't abandon iOS for Android.

In court filings from Epic Games, as part of its legal dispute with Apple, Epic argued that Apple locks customers into its ecosystem of devices and that it uses iMessage as a way of doing so. To support its argument, Epic cited writings from three high-ranking leaders at Cupertino: Eddy Cue, Apple’s senior vice president of Internet Software and Services; Craig Federighi, Apple's senior vice president of software engineering; and Apple Fellow Phil Schiller.

“The No. 1 most difficult [reason] to leave the Apple universe app is iMessage ... iMessage amounts to serious lock-in,” said one unnamed former Apple employee in an email from 2016, to which Schiller responded with: “Moving iMessage to Android will hurt us more than help us, this email illustrates why".

Meanwhile, Federighi once said: “iMessage on Android would simply serve to remove [an] obstacle to iPhone families giving their kids Android phones".

According to Epic’s filing, Eddy Cue even admitted Apple "could have made a version [of iMessage] on Android that worked with iOS” so that “users of both platforms would have been able to exchange messages with one another seamlessly". However, that has never happened, as iMessage is still iOS-only.

Epic continues to argue that services such as FaceTime also exasperate the locked-in ecosystem that Apple has created over the years.