This is very different from ActiveX. ActiveX had hundreds of exploits widely available freely on the dark parts of usenet, and exploited by every proverbial scriptkiddie in a basement against a swath of computers across the world.

iMessage has had a handful of exploits which are licensed out for extortionate amounts by people like NSO to a very small number of scummy nationstate threat actors in extremely targetted but very high-threat attacks on very high-profile targets.