I was thinking that this is mainly a US thing and then saw that the article talks about the US. Android is still more common in the rest of the world.

The article contradicts the unspecified headline in the first sentence: "It's no secret that Android is the most-used operating system in the world, a title it first earned after surpassing Windows in 2017."

This is 100% a US thing

I find it curious why this is downvoted?
IOS is a clear market leader overall in USA with 57% market share according to statcounter:
https://gs.statcounter.com/os-market-share/mobile/united-states-of-america/
It's not hard to imagine that could be even more for teenagers, that are more vulnerable about being socially left out.
And yes I too find that problematic, because Apple is a control freak company, that want's to decide what you can do with your phone. Resulting in insanity early on, that you couldn't buy the most popular newspapers in Denmark through the App store. Because they had content Apple didn't agree with!!!
How the fuck that shitshow of a company ever became so popular is beyond me, no matter how "good" their claimed quality is.

I don't know, I used to use Nokia as teenager... Things tend to change quite radically over years

Blackberry used to be all the rage with teenagers too.

It's absolutely blue bubble exceptionalism and both Apple and Google are to blame. Google couldn't focus on a single messaging strategy and has created and destroyed half a dozen workable cross-platform messaging solutions. Meanwhile, Apple did and pushed iPhone users into its walled garden while Europeans turned to Whatsapp which has the virtue of being multi-platform but it's owned by Meta which has its own set of problems.

RCS might've worked out if Google had just cut the carriers out from the beginning. It's not even that great of a protocol but it's probably the only one likely to supplant SMS as the lowest common denominator if Google gets its way with regulators and forces Apple to play along. It doesn't benefit Apple to bother until they're forced to.