"We are leading [in messaging] in most countries, but our biggest competitor by far is iMessage," Facebook (META 0.20%) CEO Mark Zuckerberg said in late 2018. "And in important countries like the U.S., where the iPhone is strong, Apple (AAPL 0.06%) bundles iMessage as the default texting app and is still ahead."

Messaging is at the center of Zuck's vision for Facebook's future. The social networking giant has grand plans to unify all of its disparate messaging services while emphasizing privacy and security. But Apple's powerful iMessage platform is an obstacle to those ambitions because it has always been the default messaging app. Some have even argued that iMessage is effectively a social network, keeping users on iOS and providing a strong disincentive to switch to Android.

Two iPhones displaying the iMessage interface

Image source: Apple.

Apple finally made a major concession this year: iOS 14 allows users to change the default apps -- but only for email and browser apps. Facebook wants the Mac maker to go a step further and allow Messenger to become the default messaging app on iPhones.

Facebook wants even more power

The Information reports that Facebook is pushing for the change, criticizing the Cupertino tech giant's restrictions and arguing that users should have more choice.

"We feel people should be able to choose different messaging apps and the default on their phone," Messenger head Stan Chudnovsky told the outlet. "Generally, everything is moving this direction anyway."

WhatsApp is wildly popular in emerging markets, hitting 2 billion monthly active users (MAUs) earlier this year. Messenger has over 1.3 billion MAUs, although that figure hasn't really grown much in recent years. It's unclear how many people use Instagram's messaging features, since that's not really what the photo- and video-sharing service is primarily used for. That's over 3 billion users who could conceivably prefer Facebook's messaging apps over iMessage.

Still, there's almost no way that Apple, which is under antitrust investigation, will give in to Facebook, which is also under antitrust investigation. iMessage is simply too strategically important, particularly as Apple continues to mimic Tencent's WeChat model, adding everything from mini apps and games to payments to Business Chat and more. iMessage has effectively evolved into a platform inside a platform, reinforcing iPhone sales and Apple's broader ecosystem of interoperability between devices.

While the antitrust scrutiny revolving around Apple primarily relates to the App Store and its 30% cut, rivals have suggested that restricting default apps undermines competition. Regulators and lawmakers have also been looking into Facebook for potential violations, including the social networking conglomerate's penchant for buying start-ups that could one day grow to become viable competitors. Acquiring a rival for the explicit purpose of reducing competition is extremely illegal, although proving that intent isn't necessarily straightforward.

Critics argue that Facebook now wields far too much market power and acts like a monopoly, which can affect everything from ad prices to consumer choice of social networking apps. Nearly half of the world's population uses one of its messaging services every month, after all.

In other words, one potential antitrust violator is pushing for another potential antitrust violator to make a concession on an antitrust issue so that it can become even stronger and exacerbate its own antitrust concerns. Got it?