You could, but why? I wrote a small package to automate my backups, and transform the content into something readable for myself. It's far from feature complete, even for my simple personal use.
But if you're doing a complete read-only copy of roam, why not go all the way and make it editable, and compete with them instead?
You could put in a lot of work, just for read-only feature parity.
Or you could work some more, and have a competing product.
You seem adamant, that the former is a better path, but I don't quite see why would you do all that work for naught.
(Roam already broke my backup script 2 times, and there are better uses of my time than interfacing with a proprietary product, if there are better alternatives.)
But if you're doing a complete read-only copy of roam, why not go all the way and make it editable, and compete with them instead?