A large undertaking such as this means financial risks, so a long-term contract -- three to five years -- must be awarded so that private firms can be assured of some measure of stability for their financial model:
What "reasonable" means is that the level of care offered by the government to the uninsured will more closely resemble the level of care offered to those who are insured (usually this means persons who are employed). Specifically, their coverage will be based on cost.
For example, a bid may specify that the private contractor intends to use cost savers such as; prior authorizations, co-pays, limits on the frequency of some types of care, limited coverage for ER visits, and so on as cost-drivers dictate. The uninsured will have a system that offers similar restrictions to what many people insured by the private sector have.