That's what some databases are. Most databases you'll see today still inevitably store the whole contents of the DB within a file with its own format, metadata, file extension, etc, or store the contents of the database within a file tree.

The notion of "lock in" being used here doesn't necessarily mean that alternatives don't or can't exist, but that comparatively, investment into development, and usage, of those systems, is drastically lower.

Think of how many modern computing systems involve filesystems as a core component of their operation, from databases, to video games, to the structure of URLs, which are essentially usually just ways to access a file tree. Now think of how many systems are in use that don't utilize files as a concept.

The very notion of files as an idea is so locked-in, that we can rarely fathom, let alone construct a system that doesn't utilize them as a part of its function.

Regardless, the files example specifically wasn't exactly meant to be a direct commentary on the state of microblogging platforms, or of all technology, but more an example for analogy purposes than anything else.

What social media platforms don't have some kind of character limit?

What platforms don't use a feed?

What platforms don't use a like button?

What platforms don't have some kind of hashtags?

All of these things are locked-in, not necessarily technologically, but socially.

Would more people from Reddit have switched to Lemmy if it didn't have upvotes and downvotes? Are there any benefits or tradeoffs to including or not including the Save button on Lemmy, and other social media sites? We don't really know, because it's substantially less explored as a concept.

The very notion of federated communities on Lemmy being instance-specific, instead of, say, instances all collectively downloading and redistributing any posts to a specific keyword acting as a sort of global community not specific to any one instance, is another instance of lock-in, adapted from the fediverse's general design around instance-specific hosting and connection.

In the world of social media, alternative platforms, such as Minus exist, that explore unique design decisions not available on other platforms, like limited total post counts, vague timestamps, and a lack of likes, but compared to all the other sites in the social media landscape, it's a drop in the bucket.

The broader point I was trying to make was just that the very way microblogging developed as a core part of social media's design means that any shift away from it likely won't actually gain traction with a mainstream audience, because of the social side of the lock-in.