Nobody's passing laws demanding a certain percentage of our power comes from fusion by 2020.
Government in these cases isn't just supporting research. It's attempting to drive a nationwide market by arbitrary decrees, most of them written by people entirely ignorant of the technologies and, for that matter, markets.
It's as if the government had demanded, at the dawn of the Space Age, that in ten years twenty percent of intercontinental commercial transport would be done by rockets.
Meanwhile, conventional energy industries are attacked, regulated into stasis, or shut down. Pipelines are stalled, drilling rigs moving overseas, and new technologies that are finally bringing domestic production back up again are being targeted for destruction.