Both schemes are funded from taxation, but they share a bill in opposite ways. A Medicare rebate is a fixed amount (example 2025: $42.85 for a standard GP visit), so any fee a doctor charges above the schedule fee becomes the patient's gap; a PBS co-payment is a fixed ceiling (example 2026: $25.00, or $7.70 with a concession card), so any price above it becomes the government's subsidy. Raise the doctor's fee and watch the gap open; switch to the PBS and raise the medicine price.
Raise the fee or the price. Watch who pays what.
Medicare fixes what the government pays for a service, while the PBS fixes what the patient pays for a medicine, and both are judged on access and equity.