Still, many people (me included) are dubious it can be done properly even with the reached goal.

As for the hypothesis:
If you're hired to build a 2 story home for 75K and you see that's not enough money, do you really want to build a shack for the money then. Or just return it and say 'that's not enough money for what you want'... the first definitely gives you angry contractors.

They created the design, they said they needed X money for it. It's not something as easily as just doing "50% GM for 50% money", that's like saying "You'll get 50% plane for 50% money... ps. It wont fly"