For many of the backers, it seems to me like that's just the risk of investing in new products/companies. If they didn't receive the promised reward for their level of contribution, that seems like a problem though.
VC's, who are professional investors and certainly better versed than the general public on how to triage projects going sideways probably have ~5% of projects totally fail, where the product never reaches production.
Kickstarter needs to manage expectations and have a solid policy on how to deal with situations like this... else, they'll be the next failure.