Though to answer the second question: there are plenty of cases (usually hardware) where people really underestimate how much things cost to make. I've lost count of the number of stories where startups said "We messed up our mold/printer/fab order which cost us $20k to redo, and then we had no money to make t-shirts".
Estimation is key on a Kickstarter. We've got a team of 4 of the best designers and developers I've ever worked with who can deliver beautiful, usable products on time.
It's the highest compliment I can pay them professionally.
Absolutely true when you rely solely on kickstarter for your funding, which is a pretty precarious situation anyway unless what you're doing is simple or inexpensive.
Though to answer the second question: there are plenty of cases (usually hardware) where people really underestimate how much things cost to make. I've lost count of the number of stories where startups said "We messed up our mold/printer/fab order which cost us $20k to redo, and then we had no money to make t-shirts".