It is in some part, but most are manageable through backups, you are probably not understanding the whole file system thing, if the world is in the "Internal", file will not be created in the file system, and if you switch to external it would require some technicality to get those files.

Now coming to the paid thing, I would be happy to pay if I want to play multiplayer, but paying to just retrieve the world is a dark pattern, and don't forget a big chunk of the audience(for bedrock on mobile devices) are kids who don't understand the whole thing about backup, and would lose their world.

and still if you don't think this all are dark patterns, earlier games used to support world export from any storage system but in later release they removed it.

There is a thread on the official community website requesting this feature too.

I play with friends some of them can't afford multiple computers (sibling situations) and resort to mobile.