Not only do I think it's relevant, I think it's the whole point. The security argument is the outcome of finding the most useful, contentious point that would support them continuing to make the gobs of money. It's the same way 'think of the children' is used for arguing in favour of various types of censorship - everyone in the know is aware it's not the real reason but we live in a society where calling someone out for BSing is considered rude, or bad politics. So the rest of us have to nod along while being treated as fools.

The TAM is saturated. Taking share from Android is difficult. Making more humans use smartphones is difficult. Making more humans is difficult. Extracting more rent is not. So the idea that the security is more important for future revenues than the ability to exploit the userbase doesn't hold up, particularly when there isn't and can't be an alternative with a different security model.