If something gets standardized, then it becomes hard to iterate on the details. You can't make incompatible changes to browser standards, or else you break comp

If something gets standardized, then it becomes hard to iterate on the details. You can't make incompatible changes to browser standards, or else you break compatibility with old web pages. React is currently working on figuring out how to adapt their API to allow asynchronous updating of the DOM. If the virtual DOM was standardized already, then the React team would have been very limited in how they could implement asynchronous rendering.