before they knew the required resources?

Or at least some finger in the air guess they would be held to no matter what else changes during the lifetime of the project.

In some ways our job is to deliver failure. We never know enough, we never will know enough, we never have enough, we never will have enough. That's the game, our role is to deliver as much as we can, as best we can, and then get asked "What have you done for me lately". No point in whining about it, it just is. Pretending it isn't, causes far more real and percieved failures than anything else.

Let's try to be real here. The key to project success in business IT, is manage the definition of success, it being something vaguely approaching one seems to be a bonus.

You find me a businessman who'll given an open ended commitment to deliver, with no idea of what, when, why or how, I've a bridge he really needs.