Mostly company phones in Europe

Does it matter? It's not like people everyone carries two phones around.

and I suspect elsewhere too.

Wishful thinking, again.

nice cherry picking of numbers with “western” Europe only…

The point is that there is a non-negligible number of people using iOS everywhere. In Brazil, it's 17%, In China, it's ~20%. In Russia, 30%. Saying that "no one uses it outside of the US and Japan" is absurd.

I would tell them to install Monal. It works fine for normal messaging.

If you "know almost no one that uses iOS privately", you are probably surrounded by people who think that "emoji support" and "reactions" are not important. Try stepping out of this bubble and see how far your can go with Monal. People expect a lot more than "normal messaging".

And no, I'm not saying this out of hate or because I prefer Matrix. I wish XMPP could be a viable alternative, just like I wish less people were locked on iOS. But no amount of wishing will change the reality. If XMPP enthusiasts really want to make it succeed then unfortunately they need to be ready for an uphill battle and be willing to spend resources to get a compelling alternative working on a hostile platform.