In a recent post, Godfrey Parkin talks about the 'prosumer/learner created learning' concepts in e-Learning and sees areas like informal learning, work-flow learning, and collaborative learning coming into vogue. He is advocating that organizations spend more of their budgets on these types of learning because there are many new technologies that make this more practical. I do agree that to a certain extent, learners find creating their own content motivating and compelling and enjoy interacting with others as well.
Johsua Porter of UIE, Brain Sparks also talks about user driven sites, folksonomies, in a recent post, pondering how it works in other online environments.
In addition to these modes of thought being hard to conceptualize and manage, I think another reason why mainstream learning professionals consider these trends and technologies interesting but unrealistic is because they are difficult to measure. Or at least, measure in a way that is significant and demonstrates value in how their collective organization looks at and evaluates learning. I think this is even more pronounced in corporate environments because by their very nature are pragmatic and focused on the bottom line.
Previous post on Folksonomies:
Folksonomies in an e-Learning Context
Dave Boggs, SyberWorks