I'm always exhausted by a migration. But I don't move off because there's an easy alternative. There never is. I do it to maintain principles, even at the cost of my social circles.

I remember back in the days of instant messaging, there were clients which let you chat with people in a manner agnostic to the underlying IM provider. I used this one:

https://adium.im/

Maybe we need similar omniclients for group chat platforms, with automated migration scripts etc. I think the ideal migration method would be to implement continuous archiving, so the platform can't block you from scraping your own chat archives.