We felt that local-first sync is a core feature of the product, and to exclude free users from that would be leaving out a huge amount of the value. So we opted to include it for everyone, but limit the amount you can store.
Not the same at all.
I can load my notes in vim and keep going should Obsidian disappear.
I can also bring my own sync, via Dropbox or Syncthing or what have you.
The same is true for Muse. When your membership expires (or you cancel it) the app reverts to free mode, which allows you to read, copy, and export all your data. But if you're over the free card limit then you can't create new content.
That said I have total respect for the Obsidian model. They're really successful for very good reason.
Is it really though? Obsidian notes are plain text. I can open them in any plain text editor I want without needing to export anything, edit them and have the changes reflected in Obsidian later. The files are located in a folder on my machine - no conversion necessary.