Apple is doing the same thing in Europe as it is the US. The difference is that people in Europe switched to WhatsApp, where people in the US stayed on SMS and got used to iMessage. It’s a group dynamic problem, not a problem that Apple is forcing upon anyone or not allowing (although it could do something against it, but why should they).

Also: not every major smartphone company in Europe is using the “same open system”, Apple is very much here as well.