> If you take the EU iOS market share of 33.3% and the number of EU citizens (448 million), you get ~150 million

That seems way too low out of 2 billion devices as per Apple to cause any splintering of iOS, it seems to be.

Devs will be targeting the lowest common denominator and also iOS usually goes as the US goes, so other than the EU getting a couple of neat alternative apps - this won’t amount to much in the grand scheme.