Re: Is there any real doubt?
It definitely can be more expensive to consolidate (in the short term).
This is because the existing data centers may be running old, outdated software, and a lot of customized systems. In the worst case scenario, you must do a rewrite, which means reverse-engineering the (undocumented) existing system.
Try copying your COBOL programs from the 70's and your flat-file databases to "the cloud". They won't run.
This is why I would expect that older, more specialized agencies like NASA will have a harder time consolidating.
Reporting on costs is also a big challenge. Many times there are hidden costs or savings (such as employee training, quality of service, etc) that are difficult to track. The existing accounting reports are also not designed to pull this type of data, so what can happen is some guy pulls a bunch of numbers into a spreadsheet.
I would expect it to cost more for some agencies to consolidate. That still doesn't mean its not worthwhile, because it forces them to address old problems that have been postponed for years.