“Iterative process” is a term of art in software development. You establish a plan for a chunk of work, execute the development work, test, repeat. It’s about breaking a huge task into a series of smaller more manageable ones.
Yup. With emphasis on "development". I would not normally consider the period directly after release to be terribly "iterative".
If the system is released, and you find yourself with a "top 50" list of things which require fixing, then you've really screwed up. Normally, you might have 5 or 10 things which could be patched in short order. That's not iterative. That's just fixing things that you got wrong. Your real iterative process at this point ought to mean that enhanced functionality is planned for the next release (in a year) with even more functionality planned in the release after that (in two years). That's iterative.
My guess is that Obamacare is badly architected. It cannot be patched. It probably can't be fixed. They'd be better off tearing it down and starting over.
As they approached release, I wonder if they had a list of Top 5 Risks. That would make interesting reading.