My fears with the situation you are describing is that we end up without a common file format, if everyone has a propietary app and/or file system then that makes transition or collaboration a pain.

We probably won't end there due to how lazy most of us are, but it's certainly something to consider

I feel like I'm way more cynical than most people around here about LLMs but if we accept the parent comment's framing, why can't we just use an LLM to write a throw-away converter to whatever new format is necessary? Yes of course it'll probably be lossy occasionally but the question will be, is that ok for the user doing the conversion?