No, most are zero-click silent exploits. They own your phone persistently then delete the incoming message that pwned you.
Literally worth millions of dollars on the wholesome greymarkets these days, possibly the most prized, just in case anyone was wondering.
A lot of dragons lurking in the dark there.
Wonder what's blocking the client side. Power efficiency? No target market since cheap LTE sticks can be had for under 20€ apiece?
Considering how tightly integrated iMessage is with iOS, it doesn't seem likely that it will really be fixed in an easy manner.
As it stands, the most recently published information about the exploits were in the image parsers. So any app that used the default image parsers may have been affected, but might not have the same ability to escalate the exploit via other exploits. Plus you get back to the lack of ubiquity of the app, and the difficulty in targeting.