I don't think the American Graffiti statistic is accurate. In terms of return on investment, it's not even in the top 5, and the Blair Witch Project was about much cheaper, and made twice as much money.

http://www.the-numbers.com/movies/records/budgets.php

According to Wikipedia, they have to spend three times as much, not 1/3 as much, which would make more sense as to why they spend all day avoiding getting things.