I think we both discount and overemphasize imagination at the same time. On one level it's viewed as "making stuff up." On the other hand there's the emphasis on how supposedly imaginative people make tons of cash.
And if you think making stuff up is the fast road to riches, I have various water-spanning properties in the Five Boroughs for sale.
I don't think most people believe in the get-rick-quick part of this stuff anymore — well, they'd better not, or they're in for some major letdown! — but I do think they are just as often, if not more so, under the sway of a delusion that is no less damaging, the idea that imagination is nothing but "making stuff up."
My reigning theory: Imagination is at least as much about keeping one's eyes open for things that go unobserved by others, and then using that as the raw material to bring into existence things that seem entirely new. Most anyone can "make stuff up"; few can truly invent.
I wonder how much of our current training in creative endeavors takes this into account. I don't get the impression that many folks in the self-pub / fan-am[ateur] space are taking this approach — not as long as the majority of self-publishing consists of dreary warmed-over versions of what's on the bestseller list.