Administrative expenses on the payer side are 7.5% of total US healthcare spending. Even under a single payer system, that number would decrease only slightly.
Bullshit single payer would vastly decrease that number. Only having one payor who has from your perspective fixed rates is going to vastly simplify that process compared to the cluster of today.
Health insurance profit would also disappear as much would their administration costs.
You would still need to determine price structures and deal with fraud but you wouldn't need to network anymore.
https://www.healthsystemtracker.org/chart-collection/u-s-spe...