I hate to tell you but the economic case for large expensive high tech fusion power is being undercut by alternative green sources such as solar, wind, and water as well as cheap oil, oil shale, coal, CO2 gasification, and other fossil fuel alternatives. Even regular nuclear fission plants face some rough economic challenges ahead. US petroleum production continues to increase and Russia is overflowing with oil and natural gas.
Possibly a more serious challenge is how to get enough capital to maintain the grid and distribution system and keep the electricity market liquid enough to prevent manipulation. For fusion to thrive, it will need to be cheap enough to make economic sense. Efficient cars, heating, insulation, and better batteries should all lead to reduced demand for electricity including lower baseload and peak power demand.
Finally the government has frequently intervened in the energy market and electric power system in the US. Standard Oil had over 90% of the oil market when it was split up anti Trust actions starting in1905. In the 1930s, the government funded the TVA, the Hoover dam and rural electification that bought power to most of country. The government also played a central role developing nuclear. This sector was heavily regulated. A somewhat deregulated power market did not get going till the 1990s. Overall this sector is not an example of pure capitalism being overtaken by the “efficiency” of joint government action. More often than not, and despite various episodes of shady profiteering and monopoly abuse, it has been a illustration of the ability of the mixed public-private model to deliver economic advances. A century of experience says a big government sponsored energy project is more the norm and certainly not the shocking death knell for a pure capitalist energy economy that never existed in the first place.