"Train a human to recognise something like a banana and they can tell you they are looking for a particular shape, size, colouration, orientation and apply those criteria using their learned knowledge of the object to identify zipped, unzipped, facing the camera or away, broken, twisted, ripe, unripe, etc. bananas."
And then you trick them with a plantain...or a carefully-sticked-back banana with something else within. We can fool humans. Machines don't stand a chance.
"This kind of "throw data at something AI" stuff is really doomed to failure, except where it really doesn't matter at all and where a human would be cheaper to employ anyway (e.g. a banana factory)."
Not necessarily. Remember that humans have continual costs and limited working hours. Why else do you think machines are replacing humans elsewhere?