How do capitalists deal with natural monopolies & utilities?

Monopoly is baked in, here. One firm is cheapest wherever massive fixed networks or immovable, scarce assets dominate. Simple sense tells us one provider is enough, and more (duplicate efforts) is just wasteful friction.

Same can be said for other fields. Network-effects concentrate banking & payment rails in a few hands. Money can be thought of as a shared language whose utility expands with uniform adoption, so 'currency competition' is likewise absurd here.

What do you propose here?