See the parent comment.
Parent comments is positing that only Google can do it with no specific argument on why it would be so. For instance, why would Samsung be barred from doing it ? What about Nothing ? Xiaomi ?
The "monopoly" argument feels like vague hand waiving to me. It's probably a complex and costly situation, but nothing close to why we don't have different browser engines on iOS for instance.
The recent revelations about Google paying 36% of revenue from iOS to Apple made me wonder if that had something to do with the browser-engine lockdown. I guess it depends on what the terms of the deal are and whether it depends on the user agents conveyed by the browsers. Apple might want to make damned sure that there's no mistaking or misrepresenting traffic from their platform.
Google did, Apple will, what stops other companies from doing it aside from effort and money ?
> and there's barely any carrier adoption
Expecting carriers to do adopt new technologies is usually a losing bet.