In the energy market things would be cheaper when replacing it with renewables, but spending billions on additional wind farms, solar, and storage has a steep initial price tag. You'd also have to spend billions on transmission to connect all the new generation to the grid. That or mass scale microgrids which would be cheaper, but still very expensive.

Expensive up-front things that save you money can be bought with loans and paid off with future savings.

Agreed, but the key difference is that this is not only massively expensive, but will require years of construction and the coordination of millions of people.

To make that happen, FERC is trying to incent the right market conditions and some are occurring naturally.