Ask HN: Why isn't there an open format for online whiteboards (Miro and Mural)?

The new remote-first world is all about Miro vs. Mural. The debate annoys me because I don't really want to be wedded to one or the other. Interchangeable file formats would be the obvious solution here, but both companies are using proprietary formats to keep my data in a walled garden. Why haven't we designed an open format for online-whiteboards, like RTF for text editors, or CSV?