[wpm]

iMessage is an entirely separate service. It’s inactive until you activate it. It costs nothing to not enable. My dad refused to turn it on until last year but his iCloud account functioned without issue so he wasn’t “punished” or dark patterned into turning it on.

Is the Camera app an antitrust issue too? Any bundled application?

[xg15]

Not an iPhone user, but if iMessage is also the sole permitted SMS client for iOS, how would you send or receive SMS messages when iMessage is disabled?

[wpm]

iMessage is a service. Messages is the SMS app, that will send iMessages to people who have it enabled.