Most writers just want to write and don't want to start maintaining servers and databases to handle the collection and storing of emails. This is why they outsource that functionality to a service like Substack.

It would be nice if services like Substack supported exportability, so when a writer eventually becomes successful enough to migrate away, or the platform itself is no longer a good fit, then there aren't any losses.

Convenience is good, but I don't want writers & readers to have to make a faustian pact every day.