You've had an architect design a one story house. The builder has built it per the specs. The house lacks only interior painting and floor coverings to be move-in ready.
You approach the architect and ask, "How much trouble would it be to add a second story?"
That is very similar to what happened with healthcare.gov.
Exactly.
Except it’s my strong suspicion that the first floor needed a lot more than paint and floor coverings when the demand was made. I don’t think they even had all of the support beams up.