Bucky, the Kickstater isn't a shop, it is startup which is being bought into. The startup may succeed, and it may not...
Similarly, a gold mine start up could be bought into (on the promise that if it hits paydirt, you get a percentage of the booty).
Now, the gold might be found, then again, it might not.. if it doesn't, you lose the investment, they abandon the mine - however someone else comes along, who takes a chance with the mine and digs a little deeper, and whereas before, you lost the lot, the new owner hits paydirt and chooses to still offer a part of what the previous deal was - they don't have to but they do.