Most people are apathetic to this sort of thing; they just want whatever content they are already getting. They'll use the official app or the web app as long as possible. Onboarding onto federated alternatives is also complicated for normies.
Doesn't change my own reasons for leaving though 🤷♀️
There was a picture of one instance's user count that was mostly a flat line until recently, now it looks like a right angle 😂. Can't remember if it was Beehaw or a different one though