The critical step to this "unlimited budget via the back door" is to bring the new system up, regardless of how far away from actual completion and stability it is, then immediately shut down the old systems, shred the hard drives and dispose of the hardware, so that no one can ever contemplate returning to the old system as a standby.
That's funny, because it's exactly what they did when they overhauled the Canadian federal employee payroll service (Phoenix). There are now egregious failures with the new system: unpaid employees, overpaid employees and incorrect amounts in year-end income tax documents.
Imagine receiving triple your salary, making sure to keep the extra money aside, because it *will* have to be reimbursed. And to add insult to injury, pay income tax on that huge amount, then fight CRA to have your tax return revised when the correction finally gets applied.