I generally think you're pretty right on. "... we can only transition and hope others follow" is basically the right idea, the right outlook.
There is a bit more bias towards audience size as the reason this is hard than I'm comfortable with though. Twitter as a medium is, in my controversial opinion, almost always a better medium than a blog.
There's a ton of counter-opinions, but I quite enjoy seeing a thread of toots, that decompose an idea into different segments. Having the tree of comments shooting off the thread adds context & shows which areas are high engagement, contested or loved, and which don't excite as much. Being able to cite specific pieces is better than most blogs permits. The granularity of threads is better than wall of texts, for me, and enables more interesting interactions. It's a richer online medium, and in my view, that's cool.
I hope over time we can start to see ActivityPub/Mastadon start to allow blogging like things that also boast more interactive capabilities than traditional blogs. Blog posts that are shareable on standards-based social media protocols, where commenting is also standards-based social media protocols, would be a huge lift, would allow for some of the memetic virality that has allowed the social media Walled Gardens to team with activity.
Making things based on standard protocols also allows for a choice of clients. Such that we can tackle the "blogs aren't realtime" challenge (which also talks about for example comments, another handled via our existing protocols!), https://news.ycombinator.com/item?id=34231569
Understanding some of the genetic makeup of Twitter & social media & trying to recapture some of the capabilities we had is important in transitioning away. I worry that "start a fucking blog", while spirited & heart-in-the-right-place, suggests a lesser path, a path that isn't as ambitious as is mandatory for survival & thriving.