@pluralistic It's worth analyzing the growth of social media platforms through the lens of a logistic adoption curve. It doesn't fit exactly the way it does for technologies whose use is largely private. The nature of social media means that it amplifies the network effect in ways that communication technologies that are used for one-on-one communication don't. As you've pointed out, we form communities on social media that don't also exist in physical spaces. And the communication of those communities persists over time in ways that physical group interactions can't.
The problem that can't be solved technologically is the formation of those relationships and communities. No matter how good an open platform is, the technology can't create those communities. You pointed out that barriers to interoperability hinders migration, probably to the point of being impossible to overcome directly. We get users on open platforms when we invite them to come, help them do it, welcome them here, and give them reasons to visit us more often.
The network effect for social media is amplified when those of us already here create reasons for others to be here with us. It's something each of us can do. We use this platform. And we invite friends to join us. It's quite literally a situation where optimism about the value of what we have can be effective in preserving and growing it.
I've watched enshittification destroy vibrant communities on other platforms. Once people give up on those communities they can't be revived, but they can be recreated the way they originally formed. We can determine where we choose to build them.
I am here on Mastodon. I will participate in building communities here. I can contribute its growth by doing what the technology and policies can't. I can be here.