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.
I highly doubt it’s the number 1 reason for iPhone purchase but also, why would Europe be regulating something that exclusively happens in the Us?
You can highly doubt all you want but go do some research on current consumer behavior after you are done doubting.