Well, I hope this doesn't come off as
too blunt, but...
Seriously, is
anyone surprised that the vast majority of human beings are freeloaders? Especially when there is no real social encouragement or reinforcement of altruistic behavior?
Keep in mind it's not a moral failure (the books were given away free, donations were optional) or necessarily any statement on the Youth of Today (we don't have any reliable demographic data). We don't even really know why most people didn't pay, since it's not like they filled out a survey. All we have in that respect is conjecture.
But really, this is the fundamental reason why a donation model just is not sustainable. The self-publishing author who is on a budget now needs to be his or her own writer, editor, retailer, manager, publicist, marketer, web master, accountant, and now fund-raiser as well? And you pretty much get, at best, a small handful of chances to request a donation, and there are no real social consequences for the readers who choose not to donate. I just don't see this as a viable model for most writers.
As to the "get inside an author's mind," it's been done. I don't recall the writer's name (though I'll keep looking if I have time), but a couple of years ago he basically posted rough drafts of a book in progress to a website, and incorporated the immediate feedback into his writing process. He may have set up a webcam as well. At any rate, I cannot imagine that any such schemes a) will really work more than a few times, after that it gets pretty boring (or at least, the novelty is gone), and b) let's face it, even a few hundred donations is not going to match up to a £50k or even £25k advance....