One architectural difference is that the single-paying entity's job would be primarily to pay. The job of the many current entities is to not pay -- and to deve

One architectural difference is that the single-paying entity's job would be primarily to pay. The job of the many current entities is to not pay -- and to develop labyrinthine, nondeterministic, unknowable structures of great complexity to that specific end. Payments for care under our for-profit system are actually called "medical loss".