I don't think written prompting will ever go away. Writing helps you organize your thoughts in a way that speaking, umm, ah, wait no, hang on, does not. Writing I can go back and change what I've already written before I hit send. Anybody who's prompted with speech for any length has been "wait no nevermind start over". So STT will get better, sure, it's already quite good. I just don't see text extry entirely going away because Human Intelligence (HI) just doesn't work in a way that speech would be the only interface.