With all due respect, a bank reconciliation or detailing of...

With all due respect, a bank reconciliation or detailing of expended items on their own would not necessarily have revealed a blowout in costs.
Proper estimates/feasability breakdowns coupled with proper project controls assessing fcast costs to complete vs budgeted costs and a simple earned value set of controls would have identified the issues, but generally only become meaningful when you are some 20-25% of the way through the project so you get a blanced view of the ups/downs and end picture.
Its easy to speculate outside of the company as to what went wrong, but from my experience in the industry, these issues tend to start with poor estimates and poor project handovers where the estimating issues would have been revealed....just IMHO