Boulder CO tried municipalization with Xcel and the gap between the city offer and Xcel position was very large. How do your figures look if you double the price and/or add in a decade tail of having to pay 25% of billing to PG&E?

The small munis you mention are in the same position as PG&E with respect to owning decades old poles and conductors with decades of life remaining. The incumbent has all the cards in this negotiation. An existing muni can do it cheaper for the obvious reasons you stated - legacy network, all the customers are close together. Buying the most profitable bits of the PG&E network at a price they would agree to would not be profitable.