IMHO Most backers are "religious" , in the sense it's spare money for them and they get some satisfaction in backing an idea,i really believe only a tiny minority of the backers really want a concrete product in the end ,otherwise I cant believe how some ridiculous projects could be backed 10xtimes the initial money asked. For businesses,backing something can be good PR too,a lot of business do it ,no matter what the outcome is.

People like me that are too paranoid or skeptical to give free money would never back anything to begin with.