Could it be that you don’t understand Instagram? My circle of friends all rely on Instagram for announcements (mostly local) in addition to seeing updates/photos/etc. Twitter just underserved this market, and Meta realized that Instagram does serve this market, badly. Right now my local politicians have to put their text posts in a square image on a story, but it would be more convenient for them and me if they could post in a text format to their existing Instagram audience.
What I expect to happen is for Instagram to expose how bad Twitter was at converting potential users, rather than for Twitter to expose that Instagram users have no overlap with their use case.