They are already a gatekeeper with core services that are required to be interoperable. Even if iMessage specifically hasn't yet been declared a core service, Apple is in the crosshairs and behavior like banning competitors will be harmful to their legal position at a very sensitive time for them.
Your link—hell, even the URL slug and headline—make it clear that this is something Google is claiming to the EU, not something the EU itself is claiming.
Yes, it's possible that the EU will rule that iMessage needs to fall under these rules, too, but citing a major competitor (who's even more under the gun for the same stuff themselves) making the argument that Apple should be restricted is, shall we say, not super persuasive on its own.
>who's even more under the gun for the same stuff themselves
Are they, though? Google allows alternative app stores on Android, they already implement an interoperable, open standard in their primary texting app (RCS), they allow alternative browsers on the Play store itself, and they don't block interoperability with other platforms the way Apple does.
That's not to say they're not under the gun, but what they're under the gun for is different, like bribing Epic and others to not move to their own app store or make a self-updating app downloadable from their website.
They're both monopolistic asshole companies, don't get me wrong, but they're using fairly different strategies.
> they already implement an interoperable, open standard in their primary texting app (RCS)
Yes, but Apple has announced they will do the same thing. That is not the same thing as interop with the actual iMessage protocol. Similarly, Google Messages does not allow interop with its encryption and newly announced sticker/effects, which remain proprietary to the Google Messages app.
You're right, my statement was factually incorrect. The correct statement is "Apple is currently fighting an effort to require iMessage to be interoperable".
The argument stands. It would be a bad idea for Apple to ban competition from iMessage, even with an attempt at plausible deniability, while they are fighting European regulators about interoperability on multiple fronts.
They are already a gatekeeper with core services that are required to be interoperable. Even if iMessage specifically hasn't yet been declared a core service, Apple is in the crosshairs and behavior like banning competitors will be harmful to their legal position at a very sensitive time for them.