Right. The systems healthcare.gov has to interface with are established and NOT subject to change. It is up to the new system to be interoperable with whats already there. And this is where this get hard: you have to be able to speak with a myriad of different systems, translate the data to and from the schema of each target system, and do it all securely and robustly. This is all much more complicated than most of the armchair critics realize.