The long fight to make Apple's iMessage compatible with all devices has raged with little to show for it. But Google (de facto leader of the charge) and other mobile operators are now leveraging the European Union's Digital Market Act (DMA), according to the Financial Times. The law, which goes into effect in 2024, requires that "gatekeepers" not favor their own systems or limit third parties from interoperating within them. Gatekeepers are any company that meets specific financial and usage qualifications, including Google's parent company Alphabet, Apple, Samsung and others.
We use it when WhatsApp has server problems every once in a while or for a round of GamePigeon.
Ironically, in Europe you'd be "missing out" on most group conversations if you'd insist on using iMessage, as most of your buddies probably have an Android phone with WhatsApp installed.