I'd wager there were other complexities purely from the govt side. When healthcare.gov launched and crashed, it was uncovered that the final definition of the laws and rules were still coming weeks before the launch and had changed dozens of times throughout.
From a purely technical perspective, there's no way to know if something "works" if it hasn't been defined or - worse! - is constantly being redefined on the fly.
From a purely technical perspective, there's no way to know if something "works" if it hasn't been defined or - worse! - is constantly being redefined on the fly.