A lot of the kickstarter money goes towards the pledge rewards: Only ~500 people got a tier that doesn't include the final game, for all others the game + goodies have to be produced and paid for. The 33k minimum amount probably was calculated to be enough to set up production and making the game for the people pledging.

Kickstarters that do not offer rewards, just to cover some development process, generally do not work as well. People want to get stuff.