The usage of iMessage in Europe is vastly inferior to the usage of it in America. I think that was a reasonable argument from Apple and the European Commission agreed. But the thing is, apple obviously wants for people to use iPhones in Europe and to use their services just like in America. But they are now very much aware that this sort of market dominance won't come for free like it does in the USA.
> the EU probe found that iMessage falls outside the legislation because it is not widely used by businesses
Apple does offer a specific service for businesses, Apple Messages for Business, but their documentation claims it's actually different from iMessage:
https://register.apple.com/resources/messages/messaging-docu...
> Apple Messages for Business differs from the widely known iMessage by being a business to end-user service. Additionally, the encryption mechanism slightly differs from a traditional iMessage.
Given that businesses can interface with AMfB using APIs rather than the Messages app on an Apple device, it seems that would fall pretty far outside the iMessage gatekeeping definition.