It's not even that though. Looks like public utilities are only offered in areas where those utilities are cheap to provide or abundant, and private utilities fill in a gap in harder to reach areas.

The study even points this out as a foot-note but then focuses on rate of price increase versus nominal price. It should not come as a surprise that in areas where utilities are less abundant the price will increase faster than in areas where that same utility is plentiful.

Or "investor owned utilities pay out c-level bonuses and dividends equal to 23% of actual costs"

Alternate headline: "Profit-seeking organizations seek profit"