Most healthcare providers accept both Medicare and private insurance, and some also accept Medicaid/Medi-Cal. Private insurance provides the most lucrative reimbursements to doctors, hospitals, and Rx providers thus keeping the system afloat(profitable) and driving innovation. Here's a breakdown of the rates different insurance providers pay from one TX study:
For Every $1 Paid by Medicare:
Private Insurance: pays 115%-200% of the Medicare rate.
Medicaid: pays 61%-81% of Medicare rate.