The first was to break them up, as was done to such as Standard Oil. Where this was not feasible, regulation was invoked. Social life could not tolerate a water distributor to charge what it liked for water, let alone to stop its delivery. But the sources of power proliferated. The generation of electricity is done by myriad, though not countless, forces.
Hydroelectric dams generate electricity.
So do coal, oil and gas. So does nuclear power. In the next wave of social adjustment to energy consumption, the tendency was to order monopoly power distributors to break up, intending competitive offspring. Con Ed in New York, as an example, was told to sell off its power-generating plants and restrict itself to distributing power. What happened was bankruptcy.