Same problems as with self-driving cars and speech recognition: it's very very hard (if not impossible) for software to parse the universe of scenarios. Said an

Same problems as with self-driving cars and speech recognition: it's very very hard (if not impossible) for software to parse the universe of scenarios. Said another way, it's never accurate enough to "work" when it's trained on the outside world. Usable output requires the kind of accuracy you only get when the process is trained in controlled environments (limited "vocabulary": fonts, layouts, languages, words, accents, geography, etc.).