I think one of the best ways of stopping lock-in is to be file-based. Obsidian is a good example of this. Users can just keep their data as is and move on with their lives.
Many people like email for a similar reason: Every message is an independent item that can be moved and copied at will, organized into folders, filtered and sorted, moved between accounts and email clients, attached to other messages, saved and loaded as files, and so on.