To add onto this, the single exception I am aware of to this rule is the result of the gas explosions in Massachusetts.

In that case the company in charge, Columbia Gas, "exited" the market but all the scuttlebutt I heard in the area was that the Mass government was threatening the corporate execution of revoking their charter, which lead to Columbia gas selling their business off at a loss to Eversource

https://en.wikipedia.org/wiki/NiSource#Massachusetts_gas_lin...