Every dollar we put into fusion could also go into all sorts of things that have nothing to do with renewable energy. For government funding, the money could g

Every dollar we put into fusion could also go into all sorts of things that have nothing to do with renewable energy. For government funding, the money could go to small fission reactors, some military project unrelated to energy, or just a reduction in the deficit. For private investment, the sort of investors interested in fusion breakthroughs would probably go for other high-risk, high-reward opportunities rather than switching to a mature industry.