Threads is going to generate a bunch of buzz and then fade after a few months because the best Twitter posters don’t have enough of an overlap on Instagram (if they use it at all).

Twitter is about the unique accumulated social graph + 15 years of habit.

Agree with your points on the distinct user bases of Twitter and Instagram. But, evolution is inevitable in social platforms. Threads on IG might carve its own niche, just like how Stories found success despite initial skepticism. Who knows tho