Even though a new solar plant would turn a modest profit, utilities have no reason to build them because adding solar to the grid hurts the profits of their existing plants by a disproportionate amount. Unlike fossil power, the sun does not get more expensive during peak times of demand, and this has been shown to drive down spot prices and cut or eliminate the profits of existing peaker plants. This is partly an effect of the fixed-price subsidized power purchase agreements that solar farms are using now, but those agreements are designed to ensure utilities will even buy the solar energy at all, rather than exploit their existing plants.
Clean energy is approaching (and in some places has already reached) grid price parity even *without* rate or tax subsidies. Remember this is competing against the fossil industry, which is subsidized directly and indirectly to the tune of $5.2 trillion per year globally. When we finally put a price on carbon to reflect the harm fossil fuels do to public health and the environment, there will be no contest and only then utilities will voluntarily replace fossil plants en masse.
A rapid transition to clean energy would result in massive stranded assets, but in the end would mean far less of our GDP going to energy, pollution, and health care, and letting us invest in things like food, water, and education. Some utilities are forward-thinking, but most will have to be dragged kicking and screaming into the future by regulators--and the regulators can only achieve this if they have the social and political mandate to create a clean energy future. This is why I say that *large scale change* is only possible if significant changes in the social and political landscape occur.