Moved the goalposts or learned that they were actually somewhere else? :-)
You are so correct - emergent learning does escape the 'prior definitions'. It is, after all, emergent :-)
Seriously, I believe that emergent learning is un-lassoo-able (if there is such a word). The concept, perhaps, but not the phenomenon. IMHO for too long educationalists and training folk have tried to box learning in so that it could be controlled. But learning is continuous and happens without us even knowing. We see directly ahead but our conscious is scanning what is happning to the left and right of us. All of that is mixed with our prior experience and learning to contextualise and create what is happening to us. This is why learning is such a fluid, individual thing.
It is also why so many students learn very quickly what they must do to satisfy the examiner, and not necessarily their own curiosity. It is also why, in my experience, there is a real need to adopt your third point - the need to recognise the truths about learning and rethink education.