This would never take off because you're capping the profit you can make as well as excluding some recovery of costs for an unsuccessful product. i.e. If you s

This would never take off because you're capping the profit you can make as well as excluding some recovery of costs for an unsuccessful product. i.e. If you spend $10 million making a movie, and will only release it when customers pledge $50 million, you're eliminating any chance of becoming a billion dollar blockbuster, and also any chance of being unsuccessful but still recouping a million dolars. Heck you could even become a cult classic 20 years later and make more money back. Also could you image crew moral if there was constantly a high chance that the thing you've spent a year working on goes completely unreleased?