While 500 million sounds really far fetched, this is the point at which projects explode with bloat and repeated code:

the separately designed databases and pieces of software from 55 contractors work together.

Factor in dealing with the multitude of state laws and companies they are interacting with, and you have a recipe for problems.

A lot of armchair quarterback technologists, but not a lot of precedent to compare computerizing a healthcare system in this way to.